floss: Implement GetRemoteWakeAllowed on adapter

This shows whether this device is capable of waking the system from
suspend. Right now, we don't allow setting to this property so always
allow wakes from devices that either implement HID or HOGP.

Bug: 244508001
Tag: #floss
Test: Verify with btclient
Change-Id: I5346990b71da6864ffeccd9d41c99f7d4f892f5c