Handle Siddhi applications being updated as a config map

[pcnfernando]

Description:
When Siddhi application is configured as a config map in Siddhi custom resource, during an update to the config map, the update flow of the Siddhi operator will not be triggered since the Siddhi custom resource was not updated, but one of its specification reference was updated.

We need to explicitly handle this case where we have to listen to changes in the object reference being used in Siddhi CRD under

apps:
  configMap: <appName>

Related Issues:
#31
#42
#62