[BUGFIX] Add label for title of "Edit metadata" link

Currently the title of the "Edit metadata" link in filelist is
hardcoded. Add a label to make it translatable.

Resolves: #60410
Releases: 6.3, 6.2
Change-Id: Id618dfcd96ae3b4558cf9d529e0cc7c3ae220f9a
Reviewed-on: http://review.typo3.org/31772
Reviewed-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Tested-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>