New tree structure with incremental addition (does not redraw whole level of a tree when things are added/removed). Currently does not work correctly for addition or removal of elements.
Clean up of import people code
Re-clean of same person related code
Merged branch 'develop' into 'feature/two-controller-tree' with conflicts resolved.
Added autocomplete search to the owner field in modals
Added custom templates and styling to autocomplete owners
Merge branch 'develop' into feature/two-controller-tree

Conflicts:
	src/ggrc/assets/javascripts/controllers/tree_view_controller.js
Story 55768220: fixed removeChild event handler for tree view
Story 55768220: Allowing for new tree children to be added/removed without redrawing existing children
Protect against bad data
Fix nullability and unique constraints in tables

These are the tables dealing with polymorphic relationships.
Add db migration for unique constraint on program_controls
Failure to map an object to another object will now show an error with friendly messaging
is_allowed_to_map now also verifies whether there an appropriate join model exists
Add association directive_controls
Temporarily disabling the control/process/system counts in popovers
InnerNav will now cache its activated widget and re-select when the nav list is replaced
Fixed counts occasionally being incorrect for LHN search (56751066)

While not an issue in local environments, the old method would kick off
multiple "refresh counts" calls whenever a search list changed -- which
is not just on object creation, but also on every search. This resulted
in two search count queries firing, with the one that arrived second
overwriting values.
Three fixes to TreeView controller

* don't use `firstElementChild`, since it's unsupported in older but
  supported browser versions
* reduce display delay of `TreeView` by:
  - removing `options.parent` to avoid circular list references which
    cause event proliferation
  - grouping `push` and `attr` operations
* ensure `child_options` is propagated to child lists
Fix splicing in changed attribute lists