Support building testing postgresql-13 on RHEL9 host

[phracek]

This pull request adds support for building and testing postgresql-13 container on RHEL9 host.

It updates also README.md documentation with references.

[phracek]

[test-all]

[phracek]

Diff between 13/Dockerfile.rhel8 and 13/Dockerfile.rhel9 is:

$ diff 13/Dockerfile.rhel8 13/Dockerfile.rhel9
1c1
< FROM ubi8/s2i-core
---
> FROM ubi9/s2i-core
31c31
<       name="rhel8/postgresql-13" \
---
>       name="rhel9/postgresql-13" \
35c35
<       usage="podman run -d --name postgresql_database -e POSTGRESQL_USER=user -e POSTGRESQL_PASSWORD=pass -e POSTGRESQL_DATABASE=db -p 5432:5432 rhel8/postgresql-13" \
---
>       usage="podman run -d --name postgresql_database -e POSTGRESQL_USER=user -e POSTGRESQL_PASSWORD=pass -e POSTGRESQL_DATABASE=db -p 5432:5432 rhel9/postgresql-13" \
45c45
< RUN yum -y module enable postgresql:13 && \
---
> RUN yum -y install postgresql && \

Diff between 13/Dockerfile.c9s and 13/Dockerfile.rhel9 is:

$ diff 13/Dockerfile.c9s 13/Dockerfile.rhel9
1c1
< FROM quay.io/sclorg/s2i-core-c9s:c9s
---
> FROM ubi9/s2i-core
31c31
<       name="sclorg/postgresql-13-c9s" \
---
>       name="rhel9/postgresql-13" \
34c34,35
<       usage="podman run -d --name postgresql_database -e POSTGRESQL_USER=user -e POSTGRESQL_PASSWORD=pass -e POSTGRESQL_DATABASE=db -p 5432:5432 sclorg/postgresql-13-c9s" \
---
>       com.redhat.license_terms="https://www.redhat.com/en/about/red-hat-end-user-license-agreements#rhel" \
>       usage="podman run -d --name postgresql_database -e POSTGRESQL_USER=user -e POSTGRESQL_PASSWORD=pass -e POSTGRESQL_DATABASE=db -p 5432:5432 rhel9/postgresql-13" \
48a50
>     yum -y reinstall tzdata && \

[phracek]

Test results for container tests:

+ echo ''
Tests for rhel9/postgresql-13:1 succeeded.
+ '[' 0 -eq 0 ']'
+ echo 'Tests for rhel9/postgresql-13:1 succeeded.'

Test results for openshift 4 tests are:

project.project.openshift.io "sclorg-test-20627" deleted
Project sclorg-test-20627 was deleted properly
Imagestream testing not supported for rhel9 environment.

OpenShift tests for rhel9/postgresql-13:1 succeeded.

[phracek]

@fila43 @hhorak Would you be willing to review this pull request. Tests are passing but feel free to go throw RHEL9 logs for sure. I did not hit any issue in logs. Thanks.

[fila43]

LGTM