Add a whitelist to add websites for which no stylebot custom CSS will be injected

[javac9]

I was struggling for some time to see why my local website doesn't show the mock google ads. It turned out the div had id='sideAd' and I noticed then a huge block of Stylebot's predefined classes/ids injected among which is surely my "sideAd".

I tried creating some rules for my local URL, just to be able to deselect it under Stylebot options, hoping that would signal Stylebot I don't want it to do anything on this site. It didn't work - Stylebot CSS still gets injected.

So let's have a whitelist where we can say: for these please act as Stylebot addon is not present at all.