Revisions modules should not rely on global settings:

* Only pass in global settings on `init`, this allows the classes to be used agnostically elsewhere
* Clean up some erroneous/weird Backbone syntax

Props ericlewis, wonderboymusic.
Fixes #30219.


git-svn-id: https://develop.svn.wordpress.org/trunk@30131 602fd350-edb4-49c9-b593-d223f7449a82