Update generic errors to include new ones, rework existing command-specific errors

[antgurevich]

We currently have a set of generic error handling in UWVerification.py, which I believe we can update to provide a bit more information to us (in the logs) and to the user. We can add a few that are used throughout a couple commands (like MissingAnyRole) and remove them from the command-specific error handling. This will clean up our code a little bit

Not super high priority, this might be incorporated when we switch to slash commands anyways depending on the parameter types