Add get_data method to ConfigManager for retrieving specific configuration keys

src/metar_navigate/utils/config_manager.py

@@ -63,4 +63,9 @@ class ConfigManager(metaclass=SingletonMeta):
         with open(f"{self.config_dir}/config.toml", "wb") as f:
             tomli_w.dump(self.__data, f)
 
+    def get_data(self,key):
+        if key in self.__data.items():
+            return {key:self.__data[key]}
+        else:
+            return None