add user.language as option

docu/login_server.api.md

@@ -235,6 +235,7 @@ with:
 		"user.last_name",
 		"user.disabled",
 		"user.email_checked",
+		"user.language"
   	]
 }
 ```
@@ -269,6 +270,7 @@ Return only the fields which are defined in request
 - `user.disabled`: User will be disabled if he wants a account delete but has transactions. Until transactions are saved in real blockchain, we need this data because the public key
 is in db only saved in state_users so if we delete this entry, validating all transactions is no longer possible. Disabled User cannot login and cannot receive transactions. 
 - `email_checked`: If user has clicked on link in verification email (register), can only transfer gradidos if email_checked is 1
+- `language`: Language Key for User, currently 'de' or 'en'
 - `errors`: array of strings if error occure 
 
 ## Login by Email Verification Code

login_server/src/cpp/JSONInterface/JsonGetUserInfos.cpp

@@ -131,6 +131,9 @@ Poco::JSON::Object* JsonGetUserInfos::handle(Poco::Dynamic::Var params)
 				auto email = user_model->getEmail();
 				jsonUser.set("identHash", DRMakeStringHash(email.data(), email.size()));
 			}
+			else if (parameterString == "user.language") {
+				jsonUser.set("language", user_model->getLanguageKey());
+			}
 		}
 		catch (Poco::Exception& ex) {
 			jsonErrorsArray.add("ask parameter invalid");