Ensure remedy controller resources have been deleted

[stoyanr]

How to categorize this PR?
/area control-plane
/kind enhancement
/priority normal
/platform azure

What this PR does / why we need it:
Ensures that all remaining remedy controller resources have been deleted before deleting the remedy controller itself.

Which issue(s) this PR fixes:
Fixes gardener/remedy-controller#32

Special notes for your reviewer:

Release note:

The controlplane controller now ensures that all remaining remedy controller resources have been deleted before deleting the remedy controller itself.

[gardener-robot-ci-1]

Thank you @stoyanr for your contribution. I will start a build for your PR. Once started, the build URL will be posted here.

[gardener-robot-ci-3]

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[gardener-robot-ci-3]

Thank you @stoyanr for updating the PR. I will start a build. Once started, the build URL will be posted here.

[gardener-robot-ci-1]

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[AndreasBurger]

So if I understand this correctly, part of the Remedy Controller is now vendored in here so that we can enhance the extension-provider to also clean up after the Remedy Controller.
On the one hand, I don't like the coupling of both components. On the other, I think this a pragmatic approach.

[rfranzke]

PR looks great, no suggestions. Do you want to add some unit test for the deletion?

[rfranzke]

@AndreasBurger The components are not coupled, or rather, what you mean with "coupled" is already in place without this PR. The Azure extension deploys the Azure remedy controller already with a specific version and a specific deployment manifest, so it already has knowledge about what the remedy controller will do.

[gardener-robot-ci-3]

Thank you @stoyanr for updating the PR. I will start a build. Once started, the build URL will be posted here.

[gardener-robot-ci-1]

A build of this pull request has started. You can check on its progress here: https://concourse.ci.gardener.cloud/teams/gardener/pipelines/gardener-extension-provider-azure-master/jobs/master-pull-request-job/builds/5

[gardener-robot-ci-1]

Thank you @stoyanr for updating the PR. I will start a build. Once started, the build URL will be posted here.

[gardener-robot-ci-1]

A build of this pull request has started. You can check on its progress here: https://concourse.ci.gardener.cloud/teams/gardener/pipelines/gardener-extension-provider-azure-master/jobs/master-pull-request-job/builds/6

[stoyanr]

@rfranzke To add unit tests, I need to generate mocks for the Actuator interface in gardener/gardener, since such don't exist yet. I could do this, however this would mean we would need a new Gardener release with the mocks before we could release the new Azure extension. Do you think it's worth the trouble? If yes, I'll do it.

[stoyanr]

Rebased on top of #141, dependency to https://github.com/stoyanr/gardener removed.

[stoyanr]

Rebased on top of master and removed "draft".

[rfranzke]

/lgtm

[rfranzke]

/needs rebase