Fetch commit message with logs_tree endpoint

What does this MR do?

Fetches the last commit message for each table row in the Vue app by using the logs_tree endpoint that already exists. We are doing it this way because the backend needed for the GraphQL endpoint needs performance improvements.

To keep this as GraphQL like as possible we use a local client query which sends an AJAX request to the logs_tree endpoint and then returns that data in the format we want.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team