Fixup registration labels
Merge pull request #1049 from ahinz/topic/fixup-reg-labels

Fixup registration labels
Remove unused UdfModel property
Add backend functionality for getting UDF collection audits
Show UDF collection audits on the plot detail sidebar
Adding trans tag in a few places
Cleanup on edits and recent user edits:

Use model display names when possible
Don't show a filtering link for models not supported by the backend
Use the UDF collection name instead of udf:pk for display model name
Show UDF collection audits on the edits and user detail pages