K8SPG-637: disable restore on pg-restore deletion

[pooknull]

https://perconadev.atlassian.net/browse/K8SPG-637

DESCRIPTION

Problem:
If user deletes pg-restore before it fails or succeeds, the operator doesn't remove .spec.backup.restore from pg.

Solution:
Add the percona.com/delete-restore finalizer to the new pg-restore objects, which will remove the required section on deletion of pg-restore if it didn't fail or succeed.

CHECKLIST

Jira

• Is the Jira ticket created and referenced properly?
• Does the Jira ticket have the proper statuses for documentation (Needs Doc) and QA (Needs QA)?
• Does the Jira ticket link to the proper milestone (Fix Version field)?

Tests

• Is an E2E test/test case added for the new feature/change?
• Are unit tests added where appropriate?

Config/Logging/Testability

• Are all needed new/changed options added to default YAML files?
• Are all needed new/changed options added to the Helm Chart?
• Did we add proper logging messages for operator actions?
• Did we ensure compatibility with the previous version or cluster upgrade process?
• Does the change support oldest and newest supported PG version?
• Does the change support oldest and newest supported Kubernetes version?

[inelpandzic]

@pooknull pls check these tests

[JNKPercona]

Test name	Status
custom-extensions	passed
custom-tls	passed
demand-backup	failure
finalizers	passed
init-deploy	passed
monitoring	passed
one-pod	failure
operator-self-healing	passed
pitr	failure
scaling	passed
scheduled-backup	failure
self-healing	passed
sidecars	passed
start-from-backup	passed
tablespaces	failure
telemetry-transfer	passed
upgrade-consistency	passed
upgrade-minor	passed
users	passed
We run 19 out of 19

commit: 2ebc2ff
image: perconalab/percona-postgresql-operator:PR-950-2ebc2ffc9