#31 API POST Intervention

* adds support for proper POST of intervention
* makes /<id> optional (required for Post)

api/utils/serializer/__init__.py

@@ -0,0 +1,7 @@
+"""
+Author: Michel Peltriaux
+Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
+Contact: michel.peltriaux@sgdnord.rlp.de
+Created on: 24.01.22
+
+"""