tools/btmgmt: Add the 'add-adv' command
tools/btmgmt: Add the 'add-adv' command

This patch introduces the 'add-adv' command which allows users to
send the MGMT "Add Advertising" command to the kernel.

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