Update E2E test to add SSH key via the API

What does this MR do?

The test previously left the browser logged in at the end of an after hook. I updated it to log out, but also to add and remove the SSH key via the API. I similarly updated other tests, and left two to fabricate via the UI (one as a test of that feature and another because it tests auditing of using that feature via the UI).

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