WIP: Bookmarks with SortableJS

[Aradiv]

This PR is a WIP rewrite of the bookmarks plugin.

There are still some issues open and stuff that needs to be fixed.

Known Bug/ToDo List

• folders can be sorted below idOthers but this will be reverted on the next refresh.
  ToDo: disallow sorting directory below idOthers
• ToDo: test Mobile
• ToDo: (optional) check loadStorage() call and remove where they are not neccessary
• ToDo: a lot more testing

[johnd0e]

Let's reserve this field to original author, and do not change unless you rewrite plugin from scratch.

You may want to introduce separate field @coauthor or @collaborator or @contributor, but then we should keep same approach through all plugins, which currently is not in case.

[MysticJay]

While this is a different issue, I added myself to a script internal history (which I still prefer), but it was not excepted either.
As scripts tend to be privately improved, extended or modified in a different ways and get shared outside of GIT and version numbers have their own lives anyway, we need to address this somehow. @johnd0e please create a separate discussion issue on this.

[johnd0e]

While working on this PR - may be you will be able to find what is root source of #241

[johnd0e]

As I can see SortableJS should support touch.
jQueryUI fails with this (though there are plugins like https://github.com/heyman/jquery-draggable-touch and https://www.npmjs.com/package/touch-dnd).