Fixed the add many licences logic
REST API for Assets - User assignmets resource
Merge branch 'develop' of github.com:quamilek/ralph_assets into bulkedit
Clean imports
Merge branch 'develop' of https://github.com/allegro/ralph_assets into develop
Merge branch 'develop' of https://github.com/allegro/ralph_assets into fix-licences

Conflicts:
	src/ralph_assets/forms_sam.py
Fixed the add many licences logic and merge migrations
Fix default niw value in Licence
Default used value
fixed 'at least on of sn, barcode' constraint
Merge pull request #259 from xliiv/sn-or-barcode

fixed sn or barcode constraint
Merge pull request #257 from quamilek/fix-licences

Fixed the add many licences logic
sort options and set default
Filter by type in admin

* Model,
* Category,
* Asset,
Merge pull request #260 from kubked/fix/categories-import

sort import options and set default
Merge pull request #262 from quamilek/feature/admin-filters

Filter by type in admin
better options matching
Merge pull request #263 from kubked/fix/categories-import

FIX better options matching
Invoice number in Licences search views.
cleaned use of AssetLookup and its derivatives