Add warning to autobone (in onboarding)

[Vyolex]

Autobone can be confusing, we want to add folowing warning to stress that people should check the resulting proportions, and not blindly trust the results.

Autobone will try to determine your proportions from a few movements you need to do. This can improve tracking precision by a lot. If done wrong, the proportions generated will also be wrong and the tracking will be bad. You can always reset proportions when standing up straight and get back do default or try to adjust them manually.

Please check if proportions look correct, like your height and leg length make sense. If not, please redo the calibration.

[Eirenliel]

We also need to make test on all autobone screens bigger and increase the timer from 15 seconds to 30 seconds.