K8SPG-691: add repo host autoscaling

[pooknull]

DESCRIPTION

This PR adds autoscaling for pgbackrest PVCs. It follows the pgdata PVC autoscaling logic.

When the AutoGrowVolumes feature gate is enabled and spec.backups.pgbackrest.repos[].volume.volumeClaimSpec.resources.limits.storage is configured:

• A script running in the pgbackrest-config container checks disk usage every five seconds.
• When usage exceeds 75%, the script calculates a new desired size by increasing the current volume size by 50% and writes it to the repo-host pod annotation suggested-pgbackrest-<repo-name>-pvc-size
• The annotation update triggers reconcile. The operator increases the PVCs resources.requests.storage to the suggested size
• The operator saves the latest suggestion in status.pgbackrest.repos[].desiredRepoVolume

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?

[JNKPercona]

Test Name	Result	Time
backup-enable-disable	passed	00:10:39
builtin-extensions	passed	00:06:45
cert-manager-tls	passed	00:09:04
custom-envs	passed	00:19:10
custom-tls	passed	00:06:14
database-init-sql	passed	00:02:59
demand-backup	passed	00:24:10
demand-backup-offline-snapshot	passed	00:17:02
dynamic-configuration	passed	00:03:29
finalizers	passed	00:04:10
init-deploy	passed	00:03:12
huge-pages	passed	00:03:00
major-upgrade-14-to-15	passed	00:11:06
major-upgrade-15-to-16	passed	00:10:48
major-upgrade-16-to-17	passed	00:11:36
major-upgrade-17-to-18	passed	00:11:32
ldap	passed	00:04:07
ldap-tls	passed	00:07:40
monitoring	passed	00:08:10
monitoring-pmm3	passed	00:09:41
one-pod	passed	00:05:47
repo-host-autogrow	passed	00:02:25
operator-self-healing	failure	01:30:13
pgbouncer-mtls	passed	00:03:26
pitr	passed	00:12:32
scaling	passed	00:05:38
scheduled-backup	passed	00:33:47
self-healing	passed	00:09:42
sidecars	passed	00:03:01
standby-pgbackrest	passed	00:19:14
standby-streaming	passed	00:13:03
start-from-backup	passed	00:12:42
tablespaces	passed	00:07:54
telemetry-transfer	passed	00:04:55
upgrade-consistency	passed	00:06:54
upgrade-minor	passed	00:08:11
users	passed	00:04:59
migration-from-crunchy-standby	passed	00:22:39
migration-from-crunchy-pv	passed	00:08:48
migration-from-crunchy-backup-restore	passed	00:16:55

Summary	Value
Tests Run	40/40
Job Duration	02:52:34
Total Test Time	07:57:37

commit: ae363f8
image: perconalab/percona-postgresql-operator:PR-1689-ae363f849