Add health mod value, rework health fluctuations

Health now fluctuates up to 4 per day, with food effects decaying to
~31% after 1 day and ~10% after 2.
Rough health conversion
Style player::mend()
Remove extra = sign
Make health have an effect on healing speed

Also stop hibernating players from healing faster than non-hibernating
ones.
Re-add sickness artifact effect
Move healthy and healthy_mod to a creature value

Also adds the ability for health to affect effect duration.
Massive effect framework expansion

Expands effects to be able to handle everything that diseases could,
including targeted body parts and decay times
Disease move part 1 and further expansion

Expands the effects framework to allow for working stat and speed
scaling in the JSON file
Add Creature::effect_intensity/duration functions

Also convert over the "deaf" disease
Further conversion/expansion

Greatly expanded the amount of effects available, all effects use a
[normal, reduced] format except "pain", "hurt", "desc" which have
respective "reduced" values.
WIP
CRITICAL: Fix crash on opening compare menu

The game crashed when the compare menu was opened by pressing the direction key
towards a tile which contains at least one item.
Fix occasional crash (or at least I hope so)
Merge remote-tracking branch 'Wuzzy2/grammatical_number' into FrankenMod
WIP 2
Merge remote-tracking branch 'i2amroy/Health' into FrankenMod

Conflicts:
	src/creature.cpp
	src/creature.h
	src/player.cpp
	src/savegame_json.cpp
Merge pull request #7177 from Wuzzy2/mapsymbols

Change map colors of shops to have an unique color
Merge pull request #7251 from BevapDin/move-some-stuff-to-mods

Move some items from main item groups to mod specific item groups.
Actually fix crashes (Thanks Wishbringer!)