fixes #359 - hostname spoofing for unattended installation templates
fixes #3920 - prevent 500 ScopedSearch errors on the API, raise UI errors correctly
fixes #3925 - create apipie param_groups for API v2 to DRY documentation
Usergroup roles support

Working version which currently breaks a lot of tests however is ready
for testing by devs. There are still things to improve. Also we enable
users that can edit usergroups a privilege escalation atm.
Fixed tests
Add cycle detection and prevention in usergroups
Add migration for caching existing user roles
Fixed issue for redundant structures
Recache after remove

The only way to keep correct cache without complete recalculation or
having complete paths stored
With this we don't even need user_membership caching
Usergroup membership caching
Admin flag can be assigned to usergroup
Small refactorings
Roles design
Reviews
CRUD for filters
Add taxonomies to filters
Permission evaluation logic refs #3804
Autocompleting search field in filter form
WIP

Hosts authorization
Fact values authorization
Roles cleanup
Still missing link_to authorization
Fixes controller authorization
Fixes autocomplete search bar JS
Fixes unlimited filters setting