Notification dropdown

[UnspeakableHorror]

Closes https://github.com/natebenson/vyllage/issues/622.

Added notifications for the following actions:

• Posting comments on someone's resume.
• Requesting feedback from an existing user, the user will get a notification informing him of this plus the usual email.
• Requesting to add an existing user as Personal Reference.

Api docs:

• Swagger-ui.
• notifications.md
• reference-request.md

Check and uncomment notifications in _/documents/src/main/resources/documents/db/h2/migration/V11__change_usernotification.sql to test.

Other:

• Removed hardcoded sectionVersion for new comments, it was defaulting to 1 rather than using the version from the section which caused posting new comments on new sections to fail.
• Fixed a bug where tests would use users from different context causing some tests to fail.

[tylerbenson]

I don't think this should close 622, since it's likely just the backend work, right?

[UnspeakableHorror]

No, but we can open it again.

[UnspeakableHorror]

For some reason a single access check test is failing on the CIs, it runs fine locally. Once I'm done adding all the remaining tests I'll check what's wrong with it.

[tylerbenson]

This PR is a bit large for my taste. In the future try to keep it smaller.