K8SPG-613: fix .spec.initContainer

[pooknull]

https://perconadev.atlassian.net/browse/K8SPG-613

DESCRIPTION

Problem:
.spec.initContainer.resources and .spec.initContainer.containerSecurityContext are not applied to the cluster

Solution:
Apply these fields to the statefulsets.

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	00:06:47
custom-extensions	passed	00:08:56
custom-tls	passed	00:04:58
demand-backup	passed	00:24:35
finalizers	passed	00:03:49
init-deploy	passed	00:03:03
monitoring	passed	00:07:36
monitoring-pmm3	passed	00:07:24
one-pod	passed	00:05:21
operator-self-healing	passed	00:07:59
pitr	passed	00:11:39
scaling	passed	00:04:55
scheduled-backup	passed	00:28:58
self-healing	passed	00:08:59
sidecars	passed	00:02:36
start-from-backup	passed	00:13:45
tablespaces	passed	00:07:40
telemetry-transfer	passed	00:03:48
upgrade-consistency	passed	00:06:14
upgrade-minor	passed	00:05:27
users	passed	00:03:36
We run 21 out of 21		02:58:16

commit: 7218e8e
image: perconalab/percona-postgresql-operator:PR-1191-7218e8e39