Move codeclimate functions out of ee directory

What does this MR do?

We are moving the Code Quality MR widget to GitLab Core - see issue #212499 (closed)

This MR does the ~backstage backend work to make this possible.

The Code Quality MR widget uses codeclimate.head_path and codeclimate.base_path to download the JSON report artifacts for the head pipeline and base pipeline of the merge request, diffs the issues on the frontend, displays only the issues that have changed, and uses blob_path.head_path and blob_path.base_path to generate the links to the lines of code where the issues were found. In order to move this feature to core, these paths need to be moved outside of the ee directory.

How does this MR fit into the solution for the issue?

Merge Request	What's it do?
👉🏻 this MR	Backend changes to move everything needed to expose the paths to the downloadable codeclimate artifacts out of the ee directory
!36119 (merged)	Make a vuex store for the code quality mr widget to use (outside of the ee directory)
!36120 (merged)	Replace the <report-section> that currently displays the widget (inside ee) with a vue app (outside ee) that uses the vuex store from !36119 (merged) and the paths from !36114 (merged)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry is in !36120 (merged)
• [-] Documentation (if required) is in !36120 (merged)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability 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
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

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