Is your feature request related to a problem? Please describe.
When a lemmy user is banned magazine or instance wide, it does not translate to mbin at all. That means that a bad user and their content will stay publicly visible on mbin instances

Describe the solution you'd like
Federate bans and understand the lemmy activities

Describe alternatives you've considered
none

Additional context
https://join-lemmy.org/docs/contributors/05-federation.html#block-user