Separate make menu for modded crafts

[Sami]

The work for adding a separate make menu for modded crafts has been started.
It will be opened up by the key-command O and will work exactly the same way as the existing original [M]ake menu, expect that it will be reserved for modded content only and will be blank/unavailable unless there's some content to added in.

The existing method of adding modded items to the original [M]ake menu with diy_*.txt and menudef_*.txt files will works the same as always, so there are no changes required for your mods unless you want to have them appear in the new separate mOdded crafts menu.

To add items to mOdded crafts menu only the file naming needs to be changed. The modding and sub-menu definition syntax itself remains the same.
Shortly, you'll be now using mod_diy_*.txt and mod_menudef_*.txt file names to assign the items to the mOdded crafts menu.
It will be basically simple as that. For a modder.
Within the actual code I believe there's still work for a week or two, if everything goes smoothly, but the preliminary setup and plans are clear already.

These are future features - not yet functional in current version 3.85.