Add switch to /userinfo to make it ephemeral

[db0]

Currently /userinfo is always displayed for everyone, which is not always necessary. For example when as a mod I want to discover someone's account so I can check their suspicion etc.

Request: Add a bool which will turn the /userinfo results ephemeral.

[ZeldaFan0225]

i don't see how this is neccessary since theres a delete button on the message so if you don't want everybody to see it just delete it

[db0]

Well, it still shows up even for a bit, so it can get in the way of flowing discussions and people have plenty of time to notice it.

[ZeldaFan0225]

added in c479ace