Feature: Add customisable icons in topology (#193)

* [up] add config for custom images, better js

* [up] use bundler to bundle js

* [fix] remove domcontentloaded since defer is used

* [fix] formatting with black

* [fix] images drf api

* [up] add support for custom icons on additional roles: power panel, power feed, circuit

* [up] optimize topology generation by using `_id` when trying to access pk of related object

* [fix] kebab case instead of slugification

* [fix] use empty queryset in api views & change coord save logic

netbox_topology_views/api/urls.py

@@ -1,8 +1,10 @@
-from rest_framework import routers
-from . import views
+from netbox.api.routers import NetBoxRouter
 
-router = routers.DefaultRouter()
+from netbox_topology_views.api import views
 
-router.register('save-coords', views.SaveCoordsViewSet, basename='save_coords')
+router = NetBoxRouter()
 
-urlpatterns = router.urls
+router.register("save-coords", views.SaveCoordsViewSet)
+router.register("images", views.SaveRoleImageViewSet)
+
+urlpatterns = router.urls