DBACLD-155807 validate instructions for using keycloak with ODM

[fredmerci]

I followed the instructions for Openshift using routes and came up with the following changes/suggestions:

• added the file keycloak.yaml and explained how to use it to deploy keycloak to solve a problem accessing the Admin console behind a reverse proxy set up for TLS termination. (keycloak does not take into account the 'Forward' header otherwise and use the wrong scheme (http instead of https) to access some resource files)

• in keycloak-odm-script.zip:

  • update generateTemplate.sh
    • make generateTemplate.sh executable
    • replace USER_ID by USERID_CLAIM
    • display a msg if USERID_CLAIM is not provided telling that the default value preferred_username is used
    • reformulate the usage help
  • update templates/openIdWebSecurity.xml
    • replace KEYCLOAK_USERID by KEYCLOAK_USERID_CLAIM

• miscellaneous reformulations