android/README: Add "Customization" section
android/README: Add "Customization" section

pstglia/external-bluetooth-bluez,pkarasev3/bluez,silent-snowman/bluez,ComputeCycles/bluez,silent-snowman/bluez,pstglia/external-bluetooth-bluez,pkarasev3/bluez,mapfau/bluez,mapfau/bluez,pstglia/external-bluetooth-bluez,ComputeCycles/bluez,mapfau/bluez,silent-snowman/bluez,ComputeCycles/bluez,pstglia/external-bluetooth-bluez,ComputeCycles/bluez,silent-snowman/bluez,pkarasev3/bluez,mapfau/bluez,pkarasev3/bluez