[Feature Request] Add possibility to save commands in menu

I added the possibility to save commands in menu in this commit https://github.com/keremet/xfce4-terminal/commit/9694a5d9696e6153f3f1c87a802f42e03504e8a7 Merge it please.

Users will be able to add, remove, change, reorder their own menu items to paste frequently used text in terminal quickly. Users will not need to store long commands in separate documents or find them with Ctrl+R or create aliases.

I've no permissions to fork the project and create merge request