Bluetooth: Make use of bt_uuid_to_str

This make use of bt_uuid_to_str to when printing UUID values, to make it
simpler when it is just going to print so the patch introduces a new
function that does the conversion in place using a static variable.

Change-Id: Idfedf05a5ad201653fff2e01387f046cd5647c83
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>