Bug: Unusable "Languages" taxonomy appears in tagging drawer

[bradenmacdonald]

In a default Redwood install, out of the box users will see this when opening the tagging drawer:

The "Languages" taxonomy is unusable and uneditable.

Fix this by:

1. Hiding the "Languages" taxonomy if it is empty.

2. When there are no tags in a taxonomy, say "No tags in this taxonomy yet." in the dropdown instead of "No tags found with the search term '' ".

3. When there are no (visible) taxonomies in the tag drawer for the current user, display this message:

   To use tags, please enable a taxonomy or contact your administrator.

   the link should go to the Studio "Taxonomies" list page.