adjust operator helm chart labels & resource names

[monotek]

Description

• adjust operator helm chart labels
  • added helm default labels everywhere
  • removed "control-plane: controller-manager" label
  • added labels to crds too
• shortened resource names (see error below)
• combined rbac settings in single template file rbac.yaml and removed some code duplication
• renamed template files for better readability
• add "---" as prefix for all yaml files
• removed superfluous comments from chart.yaml and added some project links
• fix some markdown issues in the readme
• change kubeRbacProxy livenesspobe to failureThreshold: 5 (liveness and readinessprobe should never be the same)

Issues Resolved

• resources without labels fixed
  • might not be deinstalled correctly by helm
  • can't be easily selected with "kubectl -l label=value"
• to long resoure names fixed:

helm upgrade -i opensearch opensearch-operator/opensearch-operator 
Release "opensearch" does not exist. Installing it now.
Error: 1 error occurred:
	* Service "opensearch-opensearch-operator-controller-manager-metrics-service" is invalid: metadata.name: Invalid value: "opensearch-opensearch-operator-controller-manager-metrics-service": must be no more than 63 characters

Check List

• Commits are signed per the DCO using --signoff
• Unittest added for the new/changed functionality and all unit tests are successful
• Customer-visible features documented
• No linter warnings (make lint)

If CRDs are changed:

• CRD YAMLs updated (make manifests) and also copied into the helm chart
• Changes to CRDs documented

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