Add a classifier blacklist/disable derive config parameters.

Summary:
Read in a blacklist for classifiers, cache a compiled regex
which matches the blacklist.

Also allow for turning off counter/derive differencing.

Test Plan: manual

Reviewers: carl, chase, carlos

Reviewed By: carl

CC: dashboard

Maniphest Tasks: T7870, T7869

Differential Revision: http://grizzly.memsql.com/D4195