PyPI authentication with CI job tokens

What does this MR do?

This MR adds the ability to authenticate against the PyPI API endpoints using job tokens (CI_JOB_TOKEN).

The PyPI client sends it's requests using basic auth headers, so the endpoints use route_setting :authentication, job_token_allowed: :basic_auth to hit this conditional in the API auth code, allowing a job token to be looked up and used.

This route_setting is used in the other package APIs (NuGet, for example), so add job token authentication.

Screenshots

The end of a successful CI job that creates a PyPI package locally using a job token

The package that was created by the CI job using a job token

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• 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

Related #202012 (closed)