Convert butcher factor to use tool qualities instead of calculation [CR]

Fixes #7241

Implementing this as a separate quality gives content creators maximal freedom, and it shows up in the item description.

This PR does not change the actual values of the butchering, it simply ports them to json tool qualities.

Here is the list of items that allow butchering along with the butcher factor:

item name | item id | butcher factor
------------ | ------------- | -------------
honey scraper | honey_scraper | -20
electric carver (on) | carver_on | -14
hedge trimmer (on) | trimmer_on | -60
circular saw (on) | circsaw_on | -74
machete | machete | -14
diamond knife | diamond_knife | -14
diamond machete | diamond_machete | -14
diamond katana | diamond_katana | -20
tanto | tanto | -16
kris | kris | -12
wakizashi | wakizashi | -9
katana | katana | -13
rapier | rapier | -12
broadsword | broadsword | -15
makeshift machete | makeshift_machete | 38
steak knife | knife_steak | -16
butcher knife | knife_butcher | -18
combat knife | knife_combat | -30
pocket knife | pockknife | -16
makeshift knife | makeshift_knife | -14
stone knife | primitive_knife | -12
entrenching tool | e_tool | 8
trench knife | knife_trench | -24
switchblade | switchblade | -44
scythe | scythe | 22
war scythe | scythe_war | -1
sickle | sickle | -20
dive knife | diveknife | -30
toolbox | toolbox | -10
trowel | g_shovel | 4
integrated toolset | toolset | 100
hatchet | hatchet | -16
bionic claws | bio_claws_weapon | -12
monomolecular blade | bio_blade_weapon | -22
punch dagger | punch_dagger | -14
tiger claws | bagh_nakha | -14

The game automatically chooses the smallest available factor, the effects of the factor are this:

The time to butcher something is increased by `butcher factor * 5` move points (100 moves == 1 turn). Negative values decrease the butcher time accordingly. (The constant value 5 could be moved into the butchering values by multiplying every butcher quality level with 5 and removing that factor from the code.)

A positive butcher factor also decreases the effective skill that is used to determine the results of the butchering by `rng(0, factor / 5)`.