Add authentication from upstream providers (#107)

Let BasicOIDC delegate authentication to upstream providers (Google, GitHub, GitLab, Keycloak...)

Reviewed-on: #107

src/data/mod.rs

@@ -10,7 +10,9 @@ pub mod id_token;
 pub mod jwt_signer;
 pub mod login_redirect;
 pub mod open_id_user_info;
-pub mod openid_config;
+pub mod openid_primitive;
+pub mod provider;
+pub mod provider_configuration;
 pub mod remote_ip;
 pub mod session_identity;
 pub mod totp_key;