[DO NOT MERGE][CLOUD-2453][KEYCLOAK-7098] Deploy RH-SSO pod only if DB service is ready

[iankko]

This PR is performing the following:

* [CLOUD-2453][KEYCLOAK-7098] Move description of SSO_ADMIN_USERNAME,
  SSO_ADMIN_PASSWORD, SSO_SERVICE_USERNAME, and SSO_SERVICE_PASSWORD
  variables from image.yaml to os-sso/module.yaml

  These variables aren't used / referenced outside of some of os-sso,
  os-sso71, and os-sso72 modules, and for the future we want one
  common 'os-sso' module, sharing all the parts common to all
  RH-SSO images. This move is part of such unification

* [CLOUD-2453][KEYCLOAK-7098] Deploy RH-SSO pod only if DB
  service is ready, when provisioning from DB RH-SSO templates

Note: It is a replacement one for jboss-openshift/application-templates#485 one (since the RH-SSO 7.2 templates were moved, the changes need to be done against new location)

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[iankko]

The PR was updated, and should be ready for re-review.