Add OpenID claims "profile" and "email". (#16141)

* Added OpenID claims "profile" and "email".

* Splitted error.

* Added scopes_supported and claims_supported.

* Added more metadata.

Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Lauris BH <lauris@nix.lv>

templates/user/auth/oidc_wellknown.tmpl

@@ -6,5 +6,34 @@
     "response_types_supported": [
         "code",
         "id_token"
+    ],
+    "scopes_supported": [
+        "openid",
+        "profile",
+        "email"
+    ],
+    "claims_supported": [
+        "aud",
+        "exp",
+        "iat",
+        "iss",
+        "sub",
+        "name",
+        "preferred_username",
+        "profile",
+        "picture",
+        "website",
+        "locale",
+        "updated_at",
+        "email",
+        "email_verified"
+    ],
+    "code_challenge_methods_supported": [
+        "plain",
+        "S256"
+    ],
+    "grant_types_supported": [
+        "authorization_code",
+        "refresh_token"
     ]
 }