K8SPXC-1751: improve pitr logs

[pooknull]

https://perconadev.atlassian.net/browse/K8SPXC-1751

DESCRIPTION

This PR improves pitr collector logs by adding the following messages when the collector switches to a different pxc pod:
switching PITR binlog source from ... to ... because current source host ... is not healthy (not Synced/Primary)
or
switching PITR binlog source from ... to ... because host ... has the oldest available binlog

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?
• Are OpenShift compare files changed for E2E tests (compare/*-oc.yml)?

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 PXC version?
• Does the change support oldest and newest supported Kubernetes version?

[JNKPercona]

Test Name	Result	Time
auto-tuning-8-0	passed	00:20:28
allocator-8-0	passed	00:14:18
allocator-8-4	passed	00:14:10
backup-storage-tls-8-0	passed	00:22:17
cross-site-8-0	passed	00:36:57
custom-users-8-0	passed	00:12:44
demand-backup-cloud-8-0	passed	01:00:14
demand-backup-cloud-8-4	passed	01:00:42
demand-backup-cloud-pxb-8-0	passed	00:58:05
demand-backup-encrypted-with-tls-5-7	passed	00:48:36
demand-backup-encrypted-with-tls-8-0	passed	00:47:50
demand-backup-encrypted-with-tls-8-4	passed	00:58:54
demand-backup-encrypted-with-tls-pxb-5-7	passed	00:19:02
demand-backup-encrypted-with-tls-pxb-8-0	passed	00:17:53
demand-backup-encrypted-with-tls-pxb-8-4	passed	00:19:25
demand-backup-8-0	passed	00:44:22
demand-backup-flow-control-8-0	passed	00:10:47
demand-backup-flow-control-8-4	passed	00:11:24
demand-backup-parallel-8-0	passed	00:09:26
demand-backup-parallel-8-4	passed	00:10:28
demand-backup-without-passwords-8-0	passed	00:16:28
demand-backup-without-passwords-8-4	passed	00:17:07
extra-pvc-8-0	passed	00:25:05
haproxy-5-7	passed	00:14:36
haproxy-8-0	passed	00:14:36
haproxy-8-4	passed	00:14:22
init-deploy-5-7	passed	00:17:19
init-deploy-8-0	passed	00:16:54
limits-8-0	passed	00:12:37
monitoring-2-0-8-0	passed	00:24:01
monitoring-pmm3-8-0	passed	00:18:38
monitoring-pmm3-8-4	passed	00:18:50
one-pod-5-7	passed	00:14:25
one-pod-8-0	passed	00:13:19
pitr-8-0	passed	00:47:20
pitr-8-4	passed	00:47:36
pitr-pxb-8-0	passed	00:47:04
pitr-pxb-8-4	passed	00:47:13
pitr-gap-errors-8-0	passed	00:48:45
pitr-gap-errors-8-4	passed	00:49:31
proxy-protocol-8-0	passed	00:09:02
proxy-switch-8-0	passed	00:13:43
proxysql-sidecar-res-limits-8-0	passed	00:08:23
proxysql-scheduler-8-0	passed	00:28:21
pvc-resize-5-7	passed	00:18:32
pvc-resize-8-0	passed	00:16:10
recreate-8-0	passed	00:18:43
restore-to-encrypted-cluster-8-0	passed	00:27:14
restore-to-encrypted-cluster-8-4	passed	00:26:31
restore-to-encrypted-cluster-pxb-8-0	passed	00:16:27
restore-to-encrypted-cluster-pxb-8-4	passed	00:17:53
scaling-proxysql-8-0	passed	00:08:51
scaling-8-0	passed	00:11:17
scheduled-backup-5-7	passed	01:09:29
scheduled-backup-8-0	passed	01:06:19
scheduled-backup-8-4	passed	01:07:30
security-context-8-0	passed	00:27:20
smart-update1-8-0	passed	00:34:32
smart-update1-8-4	passed	00:34:27
smart-update2-8-0	passed	00:39:34
smart-update2-8-4	passed	00:39:44
smart-update3-8-0	passed	00:17:59
storage-8-0	passed	00:10:13
tls-issue-cert-manager-ref-8-0	passed	00:09:45
tls-issue-cert-manager-8-0	passed	00:10:50
tls-issue-self-8-0	passed	00:14:22
upgrade-consistency-8-0	passed	00:12:33
upgrade-consistency-8-4	passed	00:12:23
upgrade-haproxy-5-7	passed	00:26:18
upgrade-haproxy-8-0	passed	00:26:48
upgrade-proxysql-5-7	passed	00:15:24
upgrade-proxysql-8-0	passed	00:15:51
users-5-7	failure	00:00:57
users-8-0	failure	00:03:14
users-scheduler-8-4	failure	00:00:53
validation-hook-8-0	passed	00:01:33

Summary	Value
Tests Run	76/76
Job Duration	04:14:06
Total Test Time	31:43:28

commit: dbfcca1
image: perconalab/percona-xtradb-cluster-operator:PR-2399-dbfcca1d