Break up /database-access/guides/ (#41555)

Backports #38574

* Break up /database-access/guides/

Closes #17641

Organize the guides to enrolling databases in specific cloud providers
(or self-hosted databases) into separate subsections of the "Database
Actions" section, organized by cloud provider (or self-hosted).

We can later add general information to the index page of each
subsection about how Teleport database access works for each cloud
provider. The remaining guides in the "Guides" subsection have to do
with database-agnostic functionality of the Teleport Database Service.

This change also adds a redirect for each page it moves.

* Respond to greedy52 feedback

- In the "Database Access" intro page, move the self-hosted section
  first in the list of links to database-specific guides so it's less
  easy to miss.
- Change "AWS" to "Amazon" in product names.

* Fix linter issues

* Remove redirects added by the DB guide reorg

This prevents us from running into Vercel route limit issues, since the
number of redirects is large.

CHANGELOG.md

@@ -1370,14 +1370,15 @@ Teleport 14 adds database access support for ClickHouse HTTP and native (TCP)
 protocols. When using HTTP protocol, the user's query activity is captured in
 the Teleport audit log.
 
-See how to connect ClickHouse to Teleport [here](docs/pages/database-access/guides/clickhouse-self-hosted.mdx).
+See how to connect ClickHouse to Teleport
+[here](docs/pages/database-access/enroll-self-hosted-databases/clickhouse-self-hosted.mdx).
 
 #### Oracle database access audit logging support
 
 In Teleport 14, database access for Oracle integration is updated with query
 audit logging support.
 
-See documentation on how to configure it in the [Oracle guide](docs/pages/database-access/guides/oracle-self-hosted.mdx).
+See documentation on how to configure it in the [Oracle guide](docs/pages/database-access/enroll-self-hosted-databases/oracle-self-hosted.mdx).
 
 #### Limited passwordless access for local Windows users in OSS Teleport
 
@@ -3205,7 +3206,7 @@ label resources.
 
 Teleport database access now supports auto-discovery for Azure-hosted PostgreSQL
 and MySQL databases. See the [Azure
-guide](docs/pages/database-access/guides/azure-postgres-mysql.mdx) for more
+guide](docs/pages/database-access/enroll-azure-databases/azure-postgres-mysql.mdx) for more
 details.
 
 In addition, Teleport database access will now use Azure AD managed identity
@@ -3405,7 +3406,7 @@ to other supported database protocols.
 Teleport database access for SQL Server remains in Preview mode with more UX
 improvements coming in future releases.
 
-Refer to [the guide](docs/pages/database-access/guides/sql-server-ad.mdx) to set
+Refer to [the guide](docs/pages/database-access/enroll-aws-databases/sql-server-ad.mdx) to set
 up access to a SQL Server with Active Directory authentication.
 
 ### Snowflake database access (Preview)
@@ -3416,7 +3417,7 @@ standard database access features like role-based access control and audit
 logging, including query activity.
 
 Connect your Snowflake database to Teleport following the
-[documentation](docs/pages/database-access/guides/snowflake.mdx).
+[documentation](docs/pages/database-access/enroll-managed-databases/snowflake.mdx).
 
 ### Elasticache/MemoryDB database access (Preview)
 
@@ -3426,7 +3427,7 @@ MemoryDB, including auto-discovery and automatic credential management in some
 deployment configurations.
 
 Learn more about it in the [documentation](
-docs/pages/database-access/guides/redis-aws.mdx).
+docs/pages/database-access/enroll-aws-databases/redis-aws.mdx).
 
 ### Teleport Connect for server and database access (Preview)
 
@@ -3915,7 +3916,8 @@ You can now use database access to connect to a self-hosted Redis instance or
 Redis cluster and view Redis commands in the Teleport audit log. We will be
 adding support for AWS Elasticache in the coming weeks.
 
-[Self-hosted Redis guide](docs/pages/database-access/guides/redis.mdx)
+[Self-hosted Redis
+guide](docs/pages/database-access/enroll-self-hosted-databases/redis.mdx)
 
 #### SQL Server (Preview)
 
@@ -3924,15 +3926,15 @@ Directory authentication support for database access. Audit logging of query
 activity is not included in the preview release and will be implemented in a
 later 9.x release.
 
-[SQL Server guide](docs/pages/database-access/guides/sql-server-ad.mdx)
+[SQL Server guide](docs/pages/database-access/enroll-aws-databases/sql-server-ad.mdx)
 
 #### RDS MariaDB
 
 Teleport 9 updates MariaDB support with auto-discovery and connection to AWS RDS
 MariaDB databases using IAM authentication. The minimum MariaDB version that
 supports IAM authentication is 10.6.
 
-[Updated RDS guide](docs/pages/database-access/guides/rds.mdx)
+[Updated RDS guide](docs/pages/database-access/enroll-aws-databases/rds.mdx)
 
 #### Other Improvements
 
@@ -4038,7 +4040,7 @@ With RDS auto discovery Teleport database agents can automatically discover RDS
 instances and Aurora clusters in an AWS account.
 
 See updated
-[RDS guide](docs/pages/database-access/guides/rds.mdx) for
+[RDS guide](docs/pages/database-access/enroll-aws-databases/rds.mdx) for
 more information.
 
 #### WebAuthn
@@ -4142,13 +4144,13 @@ Teleport 7.0 is a major release of Teleport that contains new features, improvem
 
 Added support for [MongoDB](https://www.mongodb.com) to Teleport database access. [#6600](https://github.com/gravitational/teleport/issues/6600).
 
-View the [database access with MongoDB](docs/pages/database-access/guides/mongodb-self-hosted.mdx) for more details.
+View the [database access with MongoDB](docs/pages/database-access/enroll-self-hosted-databases/mongodb-self-hosted.mdx) for more details.
 
 #### Cloud SQL MySQL
 
 Added support for [GCP Cloud SQL MySQL](https://cloud.google.com/sql/docs/mysql) to Teleport database access. [#7302](https://github.com/gravitational/teleport/pull/7302)
 
-View the Cloud SQL MySQL [guide](docs/pages/database-access/guides/mysql-cloudsql.mdx) for more details.
+View the Cloud SQL MySQL [guide](docs/pages/database-access/enroll-google-cloud-databases/mysql-cloudsql.mdx) for more details.
 
 #### AWS Console
 
@@ -4211,7 +4213,7 @@ before upgrading.
 
 Added support for [Amazon Redshift](https://aws.amazon.com/redshift) to Teleport database access.[#6479](https://github.com/gravitational/teleport/pull/6479).
 
-View the [database access with Redshift on AWS guide](docs/pages/database-access/guides/postgres-redshift.mdx) for more details.
+View the [database access with Redshift on AWS guide](docs/pages/database-access/enroll-aws-databases/postgres-redshift.mdx) for more details.
 
 ### Improvements
 
@@ -4362,14 +4364,15 @@ With database access users can connect to PostgreSQL and MySQL databases using s
 
 ##### Getting Started
 
-Configure database access following the [Getting Started](./docs/pages/database-access/introduction.mdx#getting-started/) guide.
+Configure database access following the [Getting Started](./docs/pages/database-access/introduction.mdx#get-started/) guide.
 
 ##### Guides
 
-* [AWS RDS/Aurora PostgreSQL](./docs/pages/database-access/guides/rds.mdx)
-* [AWS RDS/Aurora MySQL](./docs/pages/database-access/guides/rds.mdx)
-* [Self-hosted PostgreSQL](./docs/pages/database-access/guides/postgres-self-hosted.mdx)
-* [Self-hosted MySQL](./docs/pages/database-access/guides/mysql-self-hosted.mdx)
+* [AWS RDS/Aurora
+  PostgreSQL](./docs/pages/database-access/enroll-aws-databases/rds.mdx)
+* [AWS RDS/Aurora MySQL](./docs/pages/database-access/enroll-aws-databases/rds.mdx)
+* [Self-hosted PostgreSQL](./docs/pages/database-access/enroll-self-hosted-databases/postgres-self-hosted.mdx)
+* [Self-hosted MySQL](./docs/pages/database-access/enroll-self-hosted-databases/mysql-self-hosted.mdx)
 * [GUI clients](docs/pages/connect-your-client/gui-clients.mdx)
 
 ##### Resources