MainHandle and SecondaryHandle sim variables for jetway stairs

Jetways are currently bone-based and the bone structure is insufficient for
rigging things like attached stairs and cables hanging from jetways. Please
consider adding XYZPBH sim variables that expose MainHandle and
SecondaryHandle rotation and translation values.
If we knew jetway elevation
angle, it would be trivial to calculate the angle of stairs and drive
corresponding animations.

This would be greatly appreciated. Main and secondary would be great for
cables and air condition hoses. Ground leg extension would maybe make stairs
even easier. I would absolutely upvote, but I don’t have any votes left.

Please consider adding this feature, it’s very much needed.

The most important thing missing from Jetways in general is still this one:

- There’s not way to know IF and WHERE a Jetway has Docked. We have the Hood
variables, which are useful to a point, to at least figure it out a Jetway
docked ( if it’s not moving and any of the hood variables are not zero, it
should have docked ), but the problem is, it doesn’t help knowing where it has
docked, or if it docked partially because it couldn’t reach the door.

This could be fixed if we had some extra SimVars for the Jetway object to
report the actual position of the bone associated to the IK_SecondaryHandle,
possibly expressed as XYZ offset from the Jetway reference point. This would
allow us to know where the jetway end is at the end of the animation.