Make the analysis of experiments more flexible

• Allow arbitrary prometheus range queres (update prometheusResponse)
• Allow usage of more than one slo checker
• Update the json which send to the python slo checker
• refactoring
• Update CRDs in order to set the query string as an dedicated parameter for a slo checker
• Update exisiting python slo checker in order to use the new JSON format (handled in !185 (merged))

Closes #249 (closed)

helm/preconfigs/oci.yaml

 operator:
   resultsVolume:
-    storageClassName: "oci-bv"
-    size: 50Gi # minimal size in OCI
\ No newline at end of file
+    persistent:
+      enabled: true
+      storageClassName: "oci-bv"
+      size: 50Gi # minimal size in OCI