[389] Post timeout

[MrGooss]

Current state Users are able to spam posts, this should be prohibited

Expected state A timeout should be added to prevent users from spamming posts

TO DO

• [x] Add attribute to backend for timeout length
• [x] Add check to backend for spam posts
• [x] Add check and warning to frontend when adding posts before timeout completes
• [ ] Add message when user is not allowed to post yet

Branch 389-post-timeout