Create a way to give deprecation warnings

[WilcoFiers]

Currently the only option is to do axe.log() and give deprecation warnings that way. The problem with that is that those messages may not be exposed to the users in all situations, or worse, they may become part of the output stream and thus making it unappeasable. We need a standard solution that different integrations can opt into. Either make it part of the results object somehow, or have it be a callback you can pass into axe? I'm not sure about the solution yet, open to suggestions.

[WilcoFiers]

We've largely deprecated use of custom evaluate / matches functions so this isn't as meaningful as it used to be. Tools have also gotten better about this, so IDEs can give these warnings for us. I don't think this ticket is important anymore.