New feature for channel hosts: warn and hide

- Send an in-app notification on Warpcast (not public, not push) to the the user directly them to your channel's norms

- We renamed Hide to Hide quietly for instances where you don't want to warn.

- Ban from channel remains unchanged

It kind of feels unreal that you're able to stay in this kind of close contact to the developer of a social network.

It's like if Zuckerberg would have been on the timeline all day talking about new features back in the day.

So glad I'm "kind of" early here!