Per Space/Room/DM privacy settings (PIN, hidden notification content...)

**Is your feature request related to a problem? Please describe.**
A user might have many Space/Room/DMs. Some of these might be categorized as personal. A user might want to set privacy settings for a specific Space/Room/DMs.

**Describe the solution you'd like**
There could be a per Space/Room/DM setting section for privacy settings such as PIN and hidden notification content.

**Additional context**
This probably shouldn't be the priority, but it would be awesome to have something like this.