WINDUP-253  Refactor WindupProcessor/Impl

Refactor WindupProcessor/Impl to simplify the API, move inner classes out and offload part of the code like prettyPrintRule() out of this important class.
Same, how about:

How about:

Loads all known {@link WindupRuleProvider} instances matching the given {@link Predicate} and returns the compiled {@link Rewrite} pipeline {@link Configuration}.