[helm chart] Remove prometheus chart dependency from Fission (#2371)

* Removing Prometheus dependency from fission chart
* User should install their own Prometheus installation
* Install Prometheus chart in Github CI workflow
* Change Prometheus query logging to debug

Signed-off-by: Sanket Sudake <sanketsudake@gmail.com>

hack/generate-helm-manifest.sh

@@ -86,7 +86,7 @@ build_yamls() {
         $command >${c}-"${version}".yaml
 
         # for OpenShift
-        command="$cmdprefix --set analytics=false,analyticsNonHelmInstall=true,logger.enableSecurityContext=true,prometheus.enabled=false"
+        command="$cmdprefix --set analytics=false,analyticsNonHelmInstall=true,logger.enableSecurityContext=true"
         echo "$command"
         $command >${c}-"${version}"-openshift.yaml