Arvados

We have a very handy feature of being able to accept OpenID access tokens and validate them with the upstream provider. We have an OpenID Connect section in the Install Guide, but it basically just points people to the configuration file for details. This section should:

• briefly explain what OpenID Connect is and how Arvados uses it
• list popular providers we know it's compatible with (so people searching for "arvados provider name" can find it)
• explain what configuration settings you must set up, and what their values are
• if there are optional values, it's okay to continue to direct people to the configuration file reference for those