Should be able to adjust host trimmings locally

[jpalawaga]

A UI or maybe even menu item to be able to manually add and remove rules from the engine.

If implemented with menus it could look like:

Rules >
   Add Host rule (twitter.com)
       Always remove "utm_source"
   Add Global rule
       Always remove "utm_source"

I think this is a pretty bad experience but might be fine to begin with. A UI would be nice as it would make it easier to manipulate and could also include a "suggest to Nakiri devs"