Add global and group policies for code analytics feature

What does this MR do?

This is one of the MRs in the series of MRs leading upto an MVC for the code analytics feature.

Originally there was one big MR reviewed by Pavel and Adam from team Analytics. It was further broken down into multiple MRs.

Here is the discovery issue on the feature https://gitlab.com/gitlab-org/gitlab-ee/issues/12683

This particular MR is part of this issue: https://gitlab.com/gitlab-org/gitlab-ee/issues/13165

Screenshots

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-