Force recipes to provide (sub)category

[jbytheway]

Summary

None

Purpose of change

As suggested in #50866, recipes without a subcategory are problematic because users might never find them.

Describe the solution

Require all recipe definitions to provide a category and subcategory when loading from JSON.

To make mandatory work properly, this entailed adding a was_loaded member to recipe. Recipes aren't loaded via generic_factory, but hopefully this is a good enough approximation to work for our purposes.

Describe alternatives you've considered

Adding a check at verification time.

Testing

Unit tests.

I didn't thoroughly check mods; will let the CI do that.

Additional context

[kevingranade]

It found one, but the error isn't super informative:

Mods-([slow] ~crafting_skill_gain)=> (continued from above) ERROR : Terminated:
Error: Mods-([slow] ~crafting_skill_gain)=> missing mandatory member "subcategory"

    "type": "recipe",
    "activity_level": "fake",
    "category": "CC_OTHER",
                           ^
    "skill_used": "fabrication",
    "difficulty": 5,
    "time": "180 m",

EDIT: Actually nevermind, the error matcher gets the file and line number from... somewhere?

[jbytheway]

Fixed that error, but because Magicylsm is tested separately from the other mods there might be more to come.

[dranitski]

found one and fixed, here is pr #51840

 DEBUG    : Error: Json error: data/mods/Aftershock/recipes/recipe_overrides.json:133:27: missing mandatory member "subcategory"

    "activity_level": "LIGHT_EXERCISE",
    "result": "foie_gras",
    "category": "CC_FOOD",
                          ^
    "skill_used": "cooking",
    "difficulty": 6,
    "charges": 1,


 FUNCTION : bool main_menu::load_character_tab(bool)
 FILE     : src/main_menu.cpp
 LINE     : 1143
 VERSION  : fe944d5

[jbytheway]

Turns out that the part of the CI that was checking mod JSON data has been broken for a while, which is why we didn't see errors outside of Magiclysm in this PR. I'm attempting to fix that in #51843.