[Feature Request] Authenticate with social providers via Open ID Connect

[enpaul]

Notesnook is an absolutely fantastic project that I've been using for a few weeks now. I've been looking for a self-hosted alternative to Google Keep for a long while now and Notesnook is truly the only contender that I've found that meets that need.

The only feature that's missing for my needs is integration with centralized authentication providers. The obvious choice for this feature would be OAuth/OpenID Connect (OIDC), but alternatives like SAML or LDAP may also be sufficient. Implementing OIDC-based authentication would benefit both the Notesnook service and self hosted instances:

• The public instance could offer sign in via popular social sites, including Google, Facebook, Github, etc
• Self-hosted instances could integrate with self-hosted OIDC providers such as Authelia, Authentik, etc

This change would likely be contained in the Streetwriters.Identity server, though I'm not nearly capable enough at C# to know exactly where this could be implemented.