[VisionGlass] Recenter view with first valid glasses pose

[svillar]

In VisionGlass the view is not properly shown "in front of" the user in cases in which the user is moving their head while Wolvic is starting. The reasons are multiple:

1. we were incorrectly getting identity quaternions sometimes in positions where the glasses orientation was not precisely that
2. the recenter caused by setting the head lock state was not issued on time, so it was not doing anything in the practice

From now on we don't render any frame until a valid head pose is received and also we do perform a full widget recenter after the first drawn frame.

[svillar]

This is not the correct approach