advertising: Detect if extended advertising mgmt commands are supported

advertising: Detect if extended advertising mgmt commands are supported

We need to know if kernel supports the new MGMT interface. To do so, we
check the return from adapter's MGMT_OP_READ_COMMANDS call for the new
commands. This will later be used to route our requests for new
advertisements.

The change is tested by manually verifying that the correct MGMT
commands are used when the feature is and is not available in kernel.

Signed-off-by: Anuj Jain <anuj01.jain@samsung.com>
Signed-off-by: Ayush Garg <ayush.garg@samsung.com>