Replacing Channels and Domains with Collection.
Moving downloading relationships from Channel to Collection.
Created domains.yaml config to manage tagged domain collections.
Adding turn-key upgrade solution in the UI.
* A new zim module has been added, this module allows several things to interact with Zim files.
* Allow searching of Zim files using libzim.
* Allow downloading of Kiwix projects (wikipedia, wikibooks, etc) on a schedule which replaces the outdated files.
* Creation of a new zim docker container which allows viewing of the Zim file contents.
* This commit also adds move/rename/mkdir features in the File Browser.
* File tags are preserved when moving/renaming.
