IALERT-3236: Address upgrade problems in helm deployments

[DanaMaxfield]

This address 3 different problems encountered while performing upgrades:

1. Centos image creates an Admin user and non-admin user as part of its standard deployment. Alpine does not do this. The user passed to the Alpine image is created is an admin. Because of this, we need to make the admin user used for the Centos DB initialization available to Alpine.
2. Centos creates a conf file (openshift-custom-postgresql.conf) that is included in postgresql.conf. This file is generated on every startup, and is stored outside of the volume. Because of this, we need to handle creating this file.
3. Centos stores its DB data in a different directory. Because of this, we had to handle being able to override this value.

** Please review ticket for testing scenarios done using the changes in this PR