[PUI] refactor table filter selector (#6047)

* Add FilterSelectDrawer component

* Add descriptions for build order table filters

* Pass active filters through via UseTable hook

* Remove old FilterGroup component

* Add callback to remove selected filter

* Implement interface for adding new filters

* Prevent duplication of filters

* Hide "add filter" elements after creating new filter

* Improved rendering

* Implement more filters for stock item table

* Add some filters for stock location table

* Refactor filter choice method

- Add StatusFilterOptions callback
- Update filters for existing tables

* purchase order table filters

* Implement more table filters

* Fix unused imports

* Render display value, not raw value

* Cleanup

* UI improvements

InvenTree/part/api.py

@@ -820,8 +820,9 @@ class PartFilter(rest_filters.FilterSet):
     def filter_has_units(self, queryset, name, value):
         """Filter by whether the Part has units or not"""
         if str2bool(value):
-            return queryset.exclude(units='')
-        return queryset.filter(units='')
+            return queryset.exclude(Q(units=None) | Q(units=''))
+
+        return queryset.filter(Q(units=None) | Q(units='')).distinct()
 
     # Filter by parts which have (or not) an IPN value
     has_ipn = rest_filters.BooleanFilter(label='Has IPN', method='filter_has_ipn')