Add django-filter to person and group tables

If there are a lot of items, you won't be able to find the needed item quickly enough currently.

added part::frontend label

changed the description

changed title from Add django-filter to people views to Add django-filter to person and group tables

It is really useful for all list views. Probably part of #73 (closed), therefore.

created merge request !321 (merged) to address this issue

mentioned in merge request !321 (merged)

assigned to @debdolph

mentioned in commit d6a0b2bd

closed via merge request !321 (merged)

mentioned in merge request Teckids/ticdesk!55