Do something with `confusables` module

[mrphlip]

There is a PyPI module for building regexes for recognising unicode confusables: https://pypi.org/project/confusables/

We should integrate that into the spam filter somehow. Like, instead of having the filter text be just regexes, have some "filter type" dropdown so you can enter regexes or plain text, and optionally have the plain text run through this confusables module.

Something to make it easier to maintain filters to catch spambots who try to hide...