SS14-17313 Chatfactor: Chat Censorship Systems (#25908)

SS14-17313 Chatfactor: Chat Censorship Systems (#25908)

* SS14-17313 Chat Censorship Systems

Adds some systems to manage chat censorship:

1. No-op: does nothing
2. SimpleCensor: a regex-free censor with a variety of rules to use
3. RegexCensor: a censor that uses regex.

This exposes a singleton backed by a builder pattern (ChatCensor) that
is set up, probably during the code init phase, and then globally available
for your censorship needs.

* Migrate to Shared

* Add a reset function to the builder.

* Resolve PJB's feedback; add unit tests