Bug 6933 [REVISED] Add a view of titles with a particular tag to the staff client

Bug 6933 [REVISED] Add a view of titles with a particular tag to the staff client

- Adds a new page to the tags moderation section for viewing all the
  titles tagged with a particular term.
- Adds display of approved tags to the catalog detail page matching the opac
  view. Adding tags from the detail view not implemented.

Follow-up adds tags display to XSLT detail view

Areas for improvement:

- I think it would be better to show "Also tagged with:" and exclude
  the current tag from the list of titles tagged with a particular tag.
- It would be nice to be able to show unapproved tags (and some idication of
  their status) along with approved tags on the detail page if the user had
  TagsModeration permission.

Signed-off-by: Nicole C. Engard <nengard@bywatersolutions.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>