Implemented new tags API

Autopsy is updated to work with the new SleuthKit tags data model in which tags are no longer blackboard artifacts. A TagsManager Autopsy service is in place as a facade for the tags related API of SleuthkitCase. The tags sub-tree of the Autopsy tree (directory tree) is rearranged. This sub-tree now consists of content and blackboard artifact tags, grouped first by tag type, then by tag name. Tags can be deleted with single select or multiple select.