Activate drift detection for helmrelease

closes #1331

This MR enables drift detection for all helm-releases defined by sylva-units by specifying it in unit_helmrelease_spec_default in sylva-units's chart values.yaml and also for the helm release of sylva-units helm release themselves.

During drift detection and then correction, if any change is made, we can get an extensive JSON Patch summary logged to the controller logs by passing the flag --log-level=debug to the controller.

Although for some units, rules to ignore drift for certain fields are added as while testing it was observed that the helm-controller was observing continuous drift for some helm releases making its's respective kustomization never finish (also mentioned in the form of comment for each unit, for which we had to add drift ignore rules).

Also, some corrections are made in monitoring and sylva-prometheus-rules (see sylva-projects/sylva-elements/helm-charts/sylva-prometheus-rules!16 (merged)) unit for certain fields for which helm release installation was getting failed because of failed dry-run.