fix(finalizer): patch finalizers instead of apply

[itamar-marom]

Description

Fixes #154

When applying the finalizers, the object generation version is bumped. We don't want that so we're patching the finalizers.

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This PR has:

• been tested on a real K8S cluster to ensure creation of a brand new Druid cluster works.
• 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

• controllers/druid/finalizers.go

[AdheipSingh]

LGTM , is this tested ?
can we confirm if the bump din't go.

[itamar-marom]

Yes. If you want to feel more confident you can just spawn a kind cluster and create the tiny-cluster.
In the old code you will see generation 2, in the new code you will see generation 1

[AdheipSingh]

@itamar-marom nah man , i trust you !