Enhance Monitor Status callback to include monitor information

[lo-simon]

Currently, the callback handlers exposed by nmos-cpp return information for all Interfaces, regardless of whether they have an associated Status Monitor. It is making it impossible to display the Interface information associated with a specific Monitor.

Current callback

typedef std::function<std::vector<nc::counter>(void)> get_packet_counters_handler;
typedef std::function<void(void)> reset_monitor_handler;

Updated callback

typedef std::function<std::vector<nc::counter>(const nmos::resource&)> get_packet_counters_handler;
typedef std::function<void(const nmos::resource&)> reset_monitor_handler;

[jonathan-r-thorpe]

LGTM