Add params to enable/disable service monitor for openshift in tektoncd/operator

https://issues.redhat.com/browse/SRVKP-1583 added this features in openshift/tektoncd-operator for 1.5 but upstream now has some new features due to which the code for mistream couldn't be merged directly upstream.

Create a separate pr in upstream to add this. this can be added after https://github.com/tektoncd/operator/pull/355 gets in. so that service monitor can be handled in openshift extention.

currently servicemonitor is part of openshift pipelines release yaml which makes it difficult to modify from extension but with pr-355 getting in, this would be easier to handle.

Acceptance Criteria

• user should be able to disable service monitor after installation
• by default operator should install it
• backward compatible with openshift-pipelines 1.5

The TektonConfig CR would look like

apiVersion: operator.tekton.dev/v1alpha1
kind: TektonConfig
metadata:
 name: config
spec:
 profile: all
 targetNamespace: openshift-pipelines
 pipeline:
   params:
   - name: enableMetrics
     value: "true"