Make auth API endpoint an environment variable

Login on webeos-proto is not working because it's connected with application-portal-qa.

Change the wordpress-image to use environment variable for the auth endpoints (similarly to OIDC_CLIENT_ID

Endpoints should be:

• production: https://auth.cern.ch
• qa: https://keycloak-qa.cern.ch

We'll need to add the new environment variable under the Golang operator

And we'll need to set it as a configuration value as well under values.yaml, so that later it can configured differently in webeos-proto and production.