Proposed title of this feature request

Allow users to scale ThanosQuerier pods provided by Cluster Observability Operator

What is the nature and description of the request?

Currently, it is not possible to scale replicas of thanos-querier pod provided by Cluster Observability Operator as the associated deployment is managed by ThanosQuerier custom resource. Scaling up the replicas of the deployment is not possible as the changes will get reverted by ThanosQuerier CR.

Also, config to change the replicas is not available in ThanosQuerier CR as well.

Why does the customer need this? (List the business requirements)

Currently, the replica of thanos-querier pods is hard coded to be 1 and can't be modified. To avoid single point of failures, it would be better to allow flexibity to scale the replicas of thanos-querier pods provided with Cluster Observability Operator. 

List any affected packages or components.

ThanosQuerier CRD (thanosqueriers.monitoring.rhobs)