net: wifi_mgmt: Support to configure AP mode parameter

Support to set BSS parameter at compile and run time.

Added support to configure `max_inactivity` BSS parameter.
Station inactivity timeout is the period for which AP may keep a client
in associated state while there is no traffic from that particular client.
If a non-zero value is set, AP may choose to disassociate the
client after the timeout.

Signed-off-by: Ajay Parida <ajay.parida@nordicsemi.no>