Organize the API shared_examples files

Proposal

Create an api directory in spec/support/shared_examples to hold all of the api specific shared_examples files. Many api shared_examples files have ended up in spec/support/api, but it makes more sense for them to live in a subdirectory of the global shared_examples folder.

What does success look like, and how can we measure that?

The shared_examples files all live in one global directory and the api specific files are in a subdirectory so they are easier to find.

References

This issue was identified in gitlab-ce!30817, specifically this discussion