Refactor update creation api

This merge request does the following:

• Raise DRF errors rather than returning response to take advantage of the DRF exception handling mechanism
• Create serialisers for PUT request to simplify the code
• Improve validation checks in several places
• Fixes several issues in DRF infrastructure uses
• Fixes JSON fields handling
• Remove routes that do no fully qualify objects
• Implement a custom DRF exception handler that will allow to log errors
• Improve testing
• Improve permission management

beat/web/experiments/serializers.py

@@ -59,7 +59,7 @@ class ExperimentCreationSerializer(serializers.ModelSerializer):
 
     class Meta:
         model = Experiment
-        beat_core_class = beat.core.experiment
+        beat_core_class = beat.core.experiment.Experiment
         fields = [
             "name",
             "short_description",