Nicknames with asterisks (*) appear as undefined at Matrix (CTCPs from undefined are broken too) / ROLEPLAY are broken

[Mikaela]

Describe the bug

Said in the title, practically #712 and #1411, except ROLEPLAY is borderline deprecated while not going to be removed from codebase.

To Reproduce
Steps to reproduce the behavior:

1. Go to room with roleplay enabled (mode +E) on a server with ROLEYPLAY enabled
2. Send NPC #channel whoever whatever or NPCA #channel whoever does whatever
3. Observe nicks who should be whoever being unknown instead

Expected behavior

The nickname appears properly

Edit: adding keyword Ergo IRCd

[emersonveenstra]

This is also matrix-org/node-irc#81, but there's more of a chance that a lot of stuff could blow up because the mxid spec says "For example, "*" is used as a wildcard in some APIs (notably the filter API), so it cannot be a legal user ID character." synapse will accept it, but we might need to encode the asterisks somehow