NET-811: block normal user login from accessing dashboard (#2724)

* block normal user login from accessing dashboard

* header change

* allow from ui header

* allow from ui header

* check for user role after decoding

* block oauth login for normal user

* handle other oauth provider callback funcs for user login

auth/github.go

@@ -66,6 +66,15 @@ func handleGithubCallback(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 	}
+	user, err := logic.GetUser(content.Email)
+	if err != nil {
+		handleOauthUserNotFound(w)
+		return
+	}
+	if !(user.IsSuperAdmin || user.IsAdmin) {
+		handleOauthUserNotAllowed(w)
+		return
+	}
 	var newPass, fetchErr = fetchPassValue("")
 	if fetchErr != nil {
 		return