[WIP] Extend ScyllaDBCluster controller with finalizer

[zimnx]

Finalizer makes sure that before ScyllaDBCluster deletion, all dependant remote Namespaces (and other resources dependant on Namespace) are removed before ScyllaDBCluster is removed.

/cc

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Finalizer makes sure that before ScyllaDBCluster deletion, all dependant remote Namespaces (and other resources dependant on Namespace) are removed before ScyllaDBCluster is removed.

/cc

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[scylla-operator-bot]

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[zimnx]

/test e2e-gke-multi-datacenter-parallel

[scylla-operator-bot]

@zimnx: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/e2e-gke-parallel-clusterip	5ff5999	link	true	/test e2e-gke-parallel-clusterip
ci/prow/e2e-gke-parallel	5ff5999	link	true	/test e2e-gke-parallel

Full PR test history. Your PR dashboard.

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