Keep stats of explicitly silenced rules

[ierceg]

Programmers may choose that some general rules are a bad fit for a particular source file. For example, since we use inheritance in our engines, lazy warns on overridden methods that don't explicitly use this (even though they use it implicitly as part of the inheritance and method overriding behaviour). In that case we have used the following construct:

//  We are implicitly using `this` in overridden methods but lazy keep telling us not to.
/* eslint class-methods-use-this: off */

This possibility however is often used to shush linters (and thus lazy) and we therefore want to keep track of this measurement.