Add support for OpenID Connect

[kulbinderdio]

Just tried this out and it all worked without a hitch, but what would be really useful to me would be if this allowed log in via OAuth. Maybe have config for different providers, e.g. Google, Facebook, etc

[9876691]

This is definitely something I'd like to add.

So I can split this into 2 pieces. Given the definitions below

OAuth 2.0: If you’ve ever signed up to a new application and agreed to let it automatically source new contacts via Facebook or your phone contacts, then you’ve likely used OAuth 2.0. This standard provides secure delegated access. That means an application can take actions or access resources from a server on behalf of the user, without them having to share their credentials. It does this by allowing the identity provider (IdP) to issue tokens to third-party applications with the user’s approval.

OpenID Connect: If you’ve used your Google to sign in to applications like YouTube, or Facebook to log into an online shopping cart, then you’re familiar with this authentication option. OpenID Connect is an open standard that organizations use to authenticate users. IdPs use this so that users can sign in to the IdP, and then access other websites and apps without having to log in or share their sign-in information.

In the first phase we could support OpenID Connect.

There's an openid example https://github.com/kilork/openid