Use JSON for favorites, move server list code to Lua (#10085)

Co-authored-by: sfan5 <sfan5@live.de>

src/script/lua_api/l_util.h

@@ -68,6 +68,9 @@ private:
 	// get_builtin_path()
 	static int l_get_builtin_path(lua_State *L);
 
+	// get_user_path()
+	static int l_get_user_path(lua_State *L);
+
 	// compress(data, method, ...)
 	static int l_compress(lua_State *L);