Add label deletion confirmation and affected items count
When destroying a label in the UI, it's not obvious how widespread the label is used. Similar to a discussion ("this will tag X people") the effect of the label deletion should be made clear to the user.
Currently:
Confirmation shown
But in the case of label cleanup, it's too easy to select the wrong label.
Options:
- put the number of affected items in the confirmation
- put the number of associated items in the rows so it's clear which one(s) (of, say, a duplicate) are the most used.

