Add redhat 9 vars file

[philippe-bourdeau]

Addresses the change for mariadb_pre_req_packages from "MySQL-python" to "python3-mysqlclient"

Provide a new vars file for RHEL 9 with working package.

Description

The package in the vars/redhat.yml is not working for RHEL 9 ; python 3 uses the python3-mysqlclient, so updating the
mariadb_pre_req_packages: from "MySQL-python" to "python3-mysqlclient" solves the issue.

Here is the error I am getting on RHEL 9.6 :

TASK [mrlesmithjr.mariadb_galera_cluster : redhat | installing pre-reqs] **************************************************************************************************************
fatal: [test-db1]: FAILED! => {"changed": false, "failures": ["No package MySQL-python available."], "msg": "Failed to install some of the specified packages", "rc": 1, "results": []}

Related Issue

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (non-breaking change that does not add functionality or fix an issue)

Checklist:

• I have read the CONTRIBUTING document.
• I have run the pre-merge tests locally and they pass.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

I am not familiar with molecule and I do not see a scenario for redhat ; I have run fedora molecule test to ensure at least one test is working and it appears to do so. I am open to add tests if you think they are required.