K8SPG-708 replace ready/live probe http check with custom command

[gkech]

CHANGE DESCRIPTION

Problem:
We are changing the probes from direct requests to patroni's restful api to a custom command so that we can get more flexibility on what can be executed for the live/ready checks of the pg container. For now this is needed so that we can introduce a sleep forever feature. Related PR: percona/percona-docker#1148

Cause:
Short explanation of the root cause of the issue if applicable.

Solution:
Short explanation of the solution we are providing with this PR.

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	Status
custom-extensions	failure
custom-tls	failure
demand-backup	failure
finalizers	failure
init-deploy	failure
monitoring	failure
monitoring-pmm3	failure
one-pod	failure
operator-self-healing	failure
pitr	failure
scaling	failure
scheduled-backup	failure
self-healing	failure
sidecars	failure
start-from-backup	failure
tablespaces	failure
telemetry-transfer	failure
upgrade-consistency	failure
upgrade-minor	failure
users	failure
We run 20 out of 20

commit: 7fa7981
image: perconalab/percona-postgresql-operator:PR-1099-7fa79815e