Closes #12246: General cleanup of utilities modules

* Clean up base modules

* Clean up forms modules

* Clean up templatetags modules

* Replace custom simplify_decimal filter with floatformat

* Misc cleanup

* Merge ReturnURLForm into ConfirmationForm

* Clean up import statements for utilities.forms

* Fix field class references in docs

netbox/utilities/query_functions.py

@@ -1,5 +1,10 @@
 from django.contrib.postgres.aggregates import JSONBAgg
-from django.db.models import F, Func
+from django.db.models import Func
+
+__all__ = (
+    'CollateAsChar',
+    'EmptyGroupByJSONBAgg',
+)
 
 
 class CollateAsChar(Func):