[Feature] Encrypted Profiles (profile picture, display name etc)

This is a feature that [Signal has also implemented](https://signal.org/blog/signal-profiles-beta/). Currently if anybody types in your username they can see your display name and profile picture. This works like a public Twitter profile, whereas many people would instead like their profile to be more like a private email address.

For privacy-conscious users this forces them to have to choose names and pictures which don't reflect their real identity, lest it be another bit of information data scrapers can retrieve.

The solution that Signal implemented allows you to selectively share your profile data with:
1. Your contacts
2. Conversations that you create, whether or not they include existing contacts
3. Other people or groups who you explicitly approve

This means sharing your profile with others is still simple yet you get the security of protected your private info from the public at large. This would also be useful for if profiles expand to have more information in the future such as bios, personal websites, other contact info, etc.