Disable crit split for mech/chassis

Crit splitting is not allowed for vehicles, but the crit split code is everywhere and needs to know if it should run or not
1. introduce a setting that refers to a tag in mech/chassis or use an existing mechanism
2. use that to enable/disable crit splitting for the mech or chassis

in general it should not be to hard to do, since crit splitting needs chassis data already, checking for disabled crit splitting should be nearby.

probably can also disable other locational data like endo steel with the same mechanism, so maybe just disable them all. maybe set to 0?