Adds Location.comments field in the required locations

- [x] 1. Add the field to the model class
- [x] 2. Generate and run database migrations
- [NA] 3. Add validation logic to clean()
- [NA] 4. Update relevant querysets
- [x] 5. Update API serializer
- [x] 6. Add fields to forms
    - [x] dcim.forms.model_forms.LocationForm, create/edit (e.g. model_forms.py)
    - [x] dcim.forms.buld_edit.LocationBulkEditForm, bulk edit
    - [x] dcim.dorms.bulk_import.LocationImportForm, CSV import
    - [x] filter (UI and API)
        - [NA] UI
            - Note: could not find any comments related things in filtersets
        - [x] API
- [x] 7. Extend object filter set
- [x] 8. Add column to object table
- [x] 9. Update the SearchIndex
- [x] 10. Update the UI templates
- [x] 11. Create/extend test cases
    - [NA] models
    - [x] views
    - [NA] forms
    - [x] filtersets
    - [x] api
- [NA] 12. Update the model's documentation

netbox/dcim/forms/bulk_import.py

@@ -160,7 +160,10 @@ class LocationImportForm(NetBoxModelImportForm):
 
     class Meta:
         model = Location
-        fields = ('site', 'parent', 'name', 'slug', 'status', 'tenant', 'facility', 'description', 'tags')
+        fields = (
+            'site', 'parent', 'name', 'slug', 'status', 'tenant', 'facility', 'description',
+            'tags', 'comments',
+        )
 
     def __init__(self, data=None, *args, **kwargs):
         super().__init__(data, *args, **kwargs)