[JavaScript] Per domain whitelist/blacklist [v1]

Fixes #98.
Fixes QupZilla/qupzilla-plugins/issues/5.

Status Bar Icons plugin for JavaScript should be also adapted to read the list (perhaps to add menu entry to add site to whitelist/blacklist).

Preview:
a.pomf.se/hqwocl.png
a.pomf.se/rqbssr.png