fix: Do not delete internal backup server on backup CR deletion

[mmorhun]

What does this PR do?

Do not set controller references on objects created by backup controller that are related to internal backup server in order to be able to reuse it for several backups in a row.

What issues does this PR fix or reference?

eclipse-che/che#18703
eclipse-che/che#19932

How to test this PR?

1. Schedule a backup by creating backup custom resource:

apiVersion: org.eclipse.che/v1
kind: CheClusterBackup
metadata:
  name: eclipse-che-backup
spec:
  useInternalBackupServer: true

2. Delete created backup CR after backup successfully finishes.
3. Make sure that internal backup server resources (deployment, backup server config and secrets) are not deleted.
4. Request another backup by creating backup CR again
5. Check that new backup created.

PR Checklist

As the author of this Pull Request I made sure that:

• The Eclipse Contributor Agreement is valid
• Code produced is complete
• Code builds without errors
• Tests are covering the bugfix
• Custom resource definition file is up to date
• Nightly OLM bundle is up to date
• The repository devfile is up to date and works
• Sections What issues does this PR fix or reference and How to test this PR completed
• Relevant user documentation updated
• Relevant contributing documentation updated
• CI/CD changes implemented, documented and communicated

Reviewers

Reviewers, please comment how you tested the PR when approving it.

[mmorhun]

/retest

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: AndrienkoAleksandr, mmorhun, tolusha

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[tolusha]

@mmorhun
I would like to see some unit tests

[tolusha]

/retest

[openshift-ci]

New changes are detected. LGTM label has been removed.

[openshift-ci]

@mmorhun: The following tests failed, say /retest to rerun all failed tests:

Test name	Commit	Details	Rerun command
ci/prow/v7-single-host-nightly-deployment	4ffa99e	link	/test v7-single-host-nightly-deployment
ci/prow/v7-multi-host-nightly-deployment	4ffa99e	link	/test v7-multi-host-nightly-deployment
ci/prow/v8-multi-host-nightly-deployment	4ffa99e	link	/test v8-multi-host-nightly-deployment
ci/prow/v8-single-host-nightly-deployment	4ffa99e	link	/test v8-single-host-nightly-deployment

Full PR test history. Your PR dashboard.

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[mmorhun]

Tests are failing due to eclipse-che/che#20072