Unify image packages, change tagging

[pathob]

The current workflow deploys two different packages, ldap-crowd-adapter and ldap-crowd-adapter-rhel. However, the package should be the same (ldap-crowd-adapter), the different OS should only be referenced by the tags of the images, e.g. ldap-crowd-adapter:7.0.1 and ldap-crowd-adapter:7.0.1-rhel.

The corresponding :latest tag for the RHEL package would then just be :rhel.

This is common practice, here some examples:

• https://hub.docker.com/_/httpd?tab=tags (see :2, :alpine and :2-alpine
• https://hub.docker.com/_/python?tab=tags (see :3.9, :alpine, :3.9-alpine, :3.9-bullseye etc.
• https://hub.docker.com/_/postgres?tab=tags (alpine and bullseye again)
• etc.