Shift towards making the tutorial work as a mod behind the scenes

[Procyonae]

Summary

Infrastructure "Tutorial content moved to a mod, keybind snippets work outside of tutorial"

Purpose of change

Hardcode bad
Tutorial stuff being loaded when not playing tutorial bad

Describe the solution

Doesn't change anything obvious player facing about the tutorial

The tutorial now loads the new mod dda_tutorial rather than just the core game, marked as obsolete so it doesn't appear on the normal mod list
All existing tutorial content I'm aware of is now contained in the mod
Blacklists all specials except the tutorial map
Prevents all external_option controllable mapgen (roads, forests etc) in the tutorial
Unhardcodes the trap triggered messages as spell triggered EoCs
Enables u_/npc_message popups to use popup flags
Allows using keybind snippets in the form <keybind:id_of_uncategorised_keybind> or <keybind:id_of_keybind_category::id_of_categorised_keybind> anywhere read by parse_tags instead of just the tutorial messages
Tweaks a couple of trap load fields that were mandatory regardless of inheritance
Adds labelling for tutorial changes, excludes them for mods label (I think someone with perms needs to actually make the label for this to do anything)

Describe alternatives you've considered

Housing the tutorial mod files somewhere other than /data/mods
I'm going to look at letting traps directly trigger EoCs in a separate PR to use in favour of via spells where not needed

Testing

Went through the tutorial, checked the rest of the map is just field, checked the tutorial trap messages still appear, checked there's no loaded mod order weirdness after save quitting etc

Additional context