Add stricter requirements to existing routes

[melroy89]

• Only allow integers on specific path routes, like for entry_id or id, etc.
• Increase safety as well
• This will also solves the 500 errors, since the path is just invalid, meaning no invalid DB calls anymore. And no unnecessary DB load. The routes are only passed to the controller if they are valid requests...

Note: For now I leave the API routes as is. And I also leave the activity_pub routes as is.. Also indirectly fixes the 23rd issue in: #1119

[melroy89]

Tested on: https://kbin.melroy.org/ (and works great!)