Nice instruction for whitelist/blacklist functionality

[liorsbg]

Maybe with a nice example page? graphics?

┆Issue is synchronized with this Asana task

[liorsbg]

An MVP of this is Critical.

[iddan]

<script
    data-whitelist="<classname>[, <classname>[n]]"
    data-blacklist="<classname>[, <classname>[n]]"
></script>

example: stylebook.de's current blacklist

<script data-blacklist=".videoPlayer, .rotatingTeaser, .OUTBRAIN"></script>

1. Selects elements by the selectors of the whitelist (default is all the elements a.k.a *)
2. Eliminates descendants of blacklist selectors