Search field for registration page

It would be nice to be able to search in the list of tickets for a specific name to quickly make an edit. Especially usefull if the list contains 100's of tickets.

Todo:
- [ ] Put the scope in the grid itself
- [x] Add the registration class and id to the TR rows
- [x] Add the filter view in the modal
- [x] Enable partial textual filters
- [x] Enable filtering by access level
- [x] Better no registrations handling
- [x] Fix table layout (to_pay field and arrows)