Accel fixes

When creating a new config because of a monitor being (un)plugged or because of super+p being pressed, honor the orientation reported by the accelerometer for the internal panel.

Before these changes we would always configure the internal panel with a normal / upright transform when e.g. an external monitor gets plugged in even if another transform was in use before plugging in the external monitor. This is inconsistent and causes problems for several use-cases. This commit fixes this by querying the accelerometer when creating a new config for an internal panel.

Fixes: #707 (closed) Fixes: #924 (closed)