Create a new `brave-ads.txt` list

[fmarier]

Now that we have entries in brave-unbreak.txt which don't related to unbreaking sites for webcompat reasons, we should have a second list whose name better reflect the purpose of these entries (e.g. brave-ads.txt or just brave.txt).

That way we're transparent about what we're doing and we're not hiding extra blocking rules in a webcompat file.

[pes10k]

Sounds good to me, though will need to have corresponding changes to https://github.com/brave/ad-block/blob/master/lists/default.h

[ryanbr]

Probably gives us time to go through the unbreak list, prune and filters that is in Easylist/Easyprivacy already.