Extend auth integration tests

[woop]

We currently have testing of authentication and authorization through unit tests on Feast Core and as part of the Python SDK e2e tests.

This issue is to track the extension of Feast Core tests to include proper client/server integration tests with a real database (postgres) as opposed to mocks.

[woop]

Lets use this issue to list out the specific test cases that we have to have in order to ensure Feast auth is minimally covered.

We should test the following as integration tests

1. Feast Core and Feast Serving with authentication enabled but no authorization. Feast Serving should send authorized requests to Feast Core. Clients to both should be forced to provide auth details.
2. Feast Core and Feast Serving with authentication and authorization enabled. We should ensure that users cannot modify feature sets in projects for which they are not members. All other functionality should remain unaffected.
3. The functionality at SDK level should be tested, including setting Google credentials or Oauth2 creds. Both towards Feast Core and Feast Serving.
4. We should have a basic load test on Feast Serving to show that there is no negative impact based on the changes we are incorporating here.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.