Add Azure configuration to docs (#1473)

docs/reference/configuration.md

@@ -42,6 +42,9 @@ This reference uses `.` to denote the nesting of values.
 * `blockstore.local.path` `(string: "~/lakefs/data")` - When using the local Block Adapter, which directory to store files in
 * `blockstore.gs.credentials_file` `(string : )` - If specified will be used as a file path of the JSON file that contains your Google service account key
 * `blockstore.gs.credentials_json` `(string : )` - If specified will be used as JSON string that contains your Google service account key (when credentials_file is not set)
+* `blockstore.azure.storage_account` `(string : )` - If specified, will be used as the Azure storage account
+* `blockstore.azure.storage_access_key` `(string : )` - If specified, will be used as the Azure storage access key
+* `blockstore.azure.endpoint` `(string : )` - If specified, custom endpoint for the Azure Blob Storage API (https://<storage_account>.<custom_domain>) 
 * `blockstore.s3.region` `(string : "us-east-1")` - When using the S3 block adapter, AWS region to use
 * `blockstore.s3.profile` `(string : )` - If specified, will be used as a [named credentials profile](https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-profiles.html)
 * `blockstore.s3.credentials_file` `(string : )` - If specified, will be used as a [credentials file](https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-files.html)
@@ -238,3 +241,31 @@ gateways:
     domain_name: s3.my-company.com
     region: us-east-1
 ```
+## Example: Azure blob storage
+
+```yaml
+---
+logging:
+  format: json
+  level: WARN
+  output: "-"
+
+database:
+  connection_string: "postgres://user:[email protected]:5432/postgres"
+
+auth:
+  encrypt:
+    secret_key: "10a718b3f285d89c36e9864494cdd1507f3bc85b342df24736ea81f9a1134bcc"
+
+blockstore:
+  type: wasb
+  azure:
+    storage_account: exampleStorageAcount
+    storage_access_key: ExampleAcessKeyMD7nkPOWgV7d4BUjzLw==
+
+gateways:
+  s3:
+    domain_name: s3.my-company.com
+    region: us-east-1
+```
+