daemon: add SmartInfo

This feature provides relevant advanced information during a call.
A user starts it with a refresh time and listens on a callback signal
to get the updated information. This information is presented in a form
of a map containing Call ID, codecs, framerate and resolution.

The public API has:
- startSmartInfo(<timeMS>)
- stopSmartInfo()
- CallSignal::SmartInfo(map) -- callback signal

Change-Id: Iaafc12b5b53aee8ad008b93536f72a4152c4ee02
Reviewed-by: Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>