[clang-tidy] Add `-verify-config` command line argument

Adds a `-verify-config` command line argument, that when specified will verify the Checks and CheckOptions fields in the config files:
 - A warning will be raised for any check that doesn't correspond to a registered check, a suggestion will also be emitted for close misses.
 - A warning will be raised for any check glob(containing *) that doesn't match any registered check.
 - A warning will be raised for any CheckOption that isn't read by any registered check, a suggestion will also be emitted for close misses.

This can be useful if debuging why a certain check isn't enabled, or the options are being handled as you expect them to be.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D127446