Ignoring users makes it harder to moderate

[iav]

Currently ignoring user work for all channels on server.
It's easy to ignore obtrusive users when you just want to joy conversation.
But then I got administrator duty on some channels, moderator duty on other. And see two choices:

1. I still ignore users annoy me on some channels — and they can do everything on channels I should moderate, I will newer see
2. I remove them from my ignore list — and will see they treats on channels where I just user.

I see 2 possible solution:

1. additional ignore list on per channel basis
2. option to disable my ignore list on channel when I have privileges to change content or privileges of other users.

[t3chguy]

Ignoring happens server-side so this would require Matrix spec changes

[aaronraimist]

Related: https://github.com/matrix-org/matrix-doc/issues/1803 #408 element-hq/element-web#11373