4A: delay service startup as a workaround to SPEC-1762/SPEC-1763 (temp workaround)

4A: delay service startup as a workaround to SPEC-1762/SPEC-1763 (temp workaround)

This patch introduces a wait loop before starting the 4A binder:
* wait for bluetooth module to be loaded
* wait for bluetooth controller to be up & running
* wait for bluetooth manager to be initialized

Then 4A can start with BT-audio support.

If no BT controller is detected in 5secondes, the loop exits and
4A doesn't initialize BT-Audio

Bug-AGL: SPEC-1762, SPEC-1763

Change-Id: Ibe851dee871d183511c7bca03411b35ed023f422
Signed-off-by: Stephane Desneux <stephane.desneux@iot.bzh>