multiple watched namespaces

[zhangluva]

Fixes #308

Description

• Fixes problem when multiple namespaces are watched
• Fixes problem when scaleStsPvc is set to true\

When multiple namespaces are watched, configured by set env.WATCH_NAMESPACE=ns1,ns2, a role needs to be created in each of the namespaces. Also, a clusterrole with list/get permission on storage.k8s.io api is needed in order for scaleStsPvc to work. All roles need to bind to the operator's service account.

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This PR has:

• [X] been tested on a real K8S cluster to ensure creation of a brand new Druid cluster works.
• [X] been tested for backward compatibility on a real K*S cluster by applying the changes introduced here on an existing Druid cluster. If there are any backward incompatible changes then they have been noted in the PR description.
• [ ] added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• [ ] added documentation for new or modified features or behaviors.

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Key changed/added files in this PR

• chart/template/role.yaml
• chart/templates/role_binding.yaml
• chart/templates/watched_namespace.yaml

[AdheipSingh]

@nishantmonu51 kindly approve to run CI