bluez-alsa: new package

bluez-alsa: new package

bluez-alsa is a Bluetooth Audio ALSA Backend.

Note that we are using the latest commit from git master branch
instead of the latest version tag v1.2.0 which is almost a year old
and is 64 commits behind master.

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
[Thomas:
 - simplify the comments in the "depends on"
 - move the Config.in comment below the hcitop option to let
   menuconfig properly indent the hcitop option under bluez-alsa]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>