floss: media: Add set device status support

Add support of setting network, roaming, signal, battery status to
btclient.

The info is stored in the Floss stack and propagated to every active
HFP device when it's changed.

Bug: 214149380
Tag: #floss
Test: HFP/AG/TRS/BV-01-C, HFP/AG/PSI/*

Change-Id: Ifd95ecad9906e9dbb9feaf545a826b4cdf91c083