GUM 61 Register clients keycloak
requested to merge feature/GUM-61-register-clients-keycloak into feature/NPD-692-gum-renovation-step-1
GUM-61 Register gazelle app in Keycloak at startup : https://gazelle.ihe.net/jira/browse/GUM-61
New classes to register the application to Keycloak on startup Added new ServiceMetadata