More consistent axes

[RisaDev]

Reported in discord:

Which axis represents which direction seems to vary between different bones. It would be nice if there was a consistent standard, at least for bones where that's easily applicable (i.e ones that aren't oriented diagonally). Bonus points if we can choose whether Y or Z is vertical.

[ecoerod]

My addition to this: would be nice to have a setting to make the axes editing world-relative and not bone-relative. I don't know if any of you have ever tried to make a shorter neck with C+, but give it a shot and you'll see why I would like this feature 😉