This commit adds new features to the breakdowner, giving animators more
control over what gets interpolated by the breakdowner. Specifically:
"Just as G R S let you move rotate scale, and then X Y Z let you do that
in one desired axis, when using the Breakdower it would be great to be
able to add GRS and XYZ to constrain what transform / axis is being
breakdowned."
As requested here:
https://rightclickselect.com/p/animation/csbbbc/breakdowner-constrain-transform-and-axis
Notes:
* In addition to G/R/S, there's also B (Bendy Bone settings and C (custom properties)
* Pressing G/R/S/B/C or X/Y/Z again will turn these constraints off again