leaudio/json: Add way to provide QoS for Sink and Source

Qos_config is a vector now.
First element is a Sink Qos and second is Source QoS.
If Source is not provided, then Sink QoS is used for Source.

Bug: 224933710
Test: atest --host bluetooth_le_audio_test
Sponsor: @jpawlowski
Change-Id: I0a439d169a2db4fbd3ea4e998af66ad75919a378
(cherry picked from commit fdc7ad32)