feat: Notifiers CRUD (#337)

* introduce scaffold for new models

* wip: shoutrrr wrapper (may remove)

* update schema files

* gen: ent code

* gen: migrations

* go mod tidy

* add group_id to notifier

* db migration

* new mapper helpers

* notifier repo

* introduce experimental adapter pattern for hdlrs

* refactor adapters to fit more common use cases

* new routes for notifiers

* update errors to fix validation panic

* go tidy

* reverse checkbox label display

* wip: notifiers UI

* use badges instead of text

* improve documentation

* add scaffold schema reference

* remove notifier service

* refactor schema folder

* support group edges via scaffold

* delete test file

* include link to API docs

* audit and update documentation + improve format

* refactor schema edges

* refactor

* add custom validator

* set validate + order fields by name

* fix failing tests

backend/app/api/handlers/v1/partials.go

@@ -21,7 +21,7 @@ func (ctrl *V1Controller) routeID(r *http.Request) (uuid.UUID, error) {
 func (ctrl *V1Controller) routeUUID(r *http.Request, key string) (uuid.UUID, error) {
 	ID, err := uuid.Parse(chi.URLParam(r, key))
 	if err != nil {
-		return uuid.Nil, validate.NewInvalidRouteKeyError(key)
+		return uuid.Nil, validate.NewRouteKeyError(key)
 	}
 	return ID, nil
 }