Remove deprecated global routes

What does this MR do?

Remove deprecated abuse_reports, invites, sent_notifications, autocomplete routes. Also remove those from reserved words.

For #210024 (closed) and #28848 (closed)

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