Connector publishing automation

[codingkarthik]

What

This PR is the first PR towards adding automating the publishing of a new connector version. The scope of this PR is limited to the following and further changes will be made in future PRs. More on the automation process here

The scope of the PR is limited to the following:

1. On opening a new PR, any new connector versions added to the registry folder according to the format specified in the doc will only be deployed to staging. This is basically to test the whole worklow. After that, we will enable the publishing process to prod after a PR is merged to the main branch.
2. Only new connector versions added are published automatically (creating a new folder under the registry/<connector_name>/releases), changes to an existing version are not covered (I'm not sure if this is useful to do anyways, since a release that has already been made never changes).
3. The README.md and logo.png changes will be made in a separate PR.

How does the automation work?

1. Whenever any PR is opened against the main branch, we get the list of files that have been added, modified and deleted. In this PR, we only use the list of added files.
2. We get the name of the connector and the version from the file path. For example: if the ndc-postgres releases v2.0.0, then one of the added files would be registry/postgres/releases/v2.0.0/connector-packaging.json , the name and version of the connector are parsed from the file path.
3. Parse the connector-packaging.json file to get the URI of the connector metadata.
4. Download the file from the URL obtained in step 3.
5. Upload the file to GCP registry and also parse the file.
6. Once all uploads are done, then insert rows into the connector versions table in the connector registry DB.
7. Connector published! 🎉 . You should be able to access the added connector version using the staging CLI.

Future work

1. Create an RFC about the file structure for connector version releases and ask the connector authors to make these changes. Once the connector authors make the changes, the connector versions will be deployed to the staging, this will be a good opportunity to test out the automation workflow.
2. Once all the connectors are updated in the registry folder according to the proposed structure in the RFC, we can enable the workflow in prod after a PR is merged to the main branch.
3. Handle changes made in the README.md and the logo.png.

[scriptnull]

feel free to remove "Work-In-Progress"