* add sign in with facebook
* feat: add facebook provider to factory function
* feat: add facebook config defaults
* feat: use newest facebook api version
* feat: make facebook provider consistent with other providers
* feat: add check for email
We cannot assume a user always has a valid email.
Even though it is not the used "me" endpoint, see:
https://developers.facebook.com/docs/graph-api/reference/user/
* docs: elaborate comment
* fix: fix third party tests
* feat: add facebook icon
* feat: add appsecret_proof to requests w. access token
* refactor: build userinfo url programmatically
* feat: map all available name claims
---------
Co-authored-by: Prathamesh <psvagare@gmail.com>
Introduce a per provider configuration option that allows users to
define whether automatic linking of accounts on sign-up/sign-in is enabled
or disabled.
