feat: use SI units as the default option

[scarf005]

Summary

SUMMARY: Interface "Change interface to use SI units as the default"

Purpose of change

give a small nudge to use SI units by setting it to be default.

• metric system is the global standard for measurement
• help players from countries outside US
• existing users wouldn't have to modify settings (probably)

Describe the solution

changed defaults as following:

Unit	Before	After
temperature	fahrenheit	celsius
speed	mph	km/h
mass	lbs	kg
distance	imperial	metric

Describe alternatives you've considered

port over DDA's

• Detect measurement units in the system locale on macOS CleverRaven/Cataclysm-DDA#58779
• Detect measurement units in user locale settings on Windows CleverRaven/Cataclysm-DDA#58784
• locale: detect measurement units with glibc CleverRaven/Cataclysm-DDA#58789

Testing

after build, checked on settings and new defaults were correct.

Additional context

blocked by #2517 until 2023-04-08 12:00:00 UTC+09:00

[chaosvolt]

Probably fair since the defaults are already a weird mix of both US and Metric measurements.

[Firestorm01X2]

I recommend to also check time format.

[scarf005]

iirc 12h is also used globally in par with 24h, so i haven't modified it.

[Zireael07]

Actually it's a little more complex than that... https://en.wikipedia.org/wiki/24-hour_clock#/media/File:12_24_Hours_World_Map.svg

Either is fine imho

[Coolthulhu]

I'd prefer the locale detection option.
If it's much more work, we could have a poll or something.

[scarf005]

I'd also prefer the locale detection but I won't be able to reliably test neither on mac nor windows.
judging by result from poll #2517, it looks like majority prefers SI units as default.

[Coolthulhu]

judging by result from poll #2517, it looks like majority prefers SI units as default.

Alright, it's OK to merge this then.