🔧 [Refactor] Disable Categories

Created by: ulfgebhardt

⚡ Refactor ticket

We have to disable Categories to be able to post again:

• Disable Categories as requirement in Posts
• Check if that will have an effect on the Dashboard/User Page etc

Most likely in a followup Ticket:

• What would be the use of Network specified Categories? Do we rly need them? @Tirokk
• How to implement them? Maybe special tags could be up for the task?
• How would we filter/display those Categories?