This adds support for the following Direct Test mode
commands:
- HCI LE Receiver Test [v3]
- HCI LE Transmitter Test [v3]
- HCI LE Transmitter Test [v4]
Those commands set add a possibility to test an CTE
reception and transmission. The HCI LE Transmitter
Test [v4] commands allows also setting a transmit power.
Signed-off-by: Kamil Gawor <Kamil.Gawor@nordicsemi.no>
