Feature/integrate google auth with grafana

Closes #325 (closed) by removing Keycloak specific assumptions from monitoring/values.yaml for the Grafana configuration.

Summary of changes:

• Check for values in grafana oauth configuration - default to keycloak values
• Selectively move default keycloak sso value definitions to the global level (namely: auth_url and token_url)
• Provide example values for using google auth in place of Keycloak (to be built on as we integrate additional apps/packages)