TPD collect bandwidth and ping for transports on re-registration / termination

[0pcom]

#38 describes re-registration interval for transports in TPD

I propose, as part of the re-registration process, that the visor report the bandwidth and ping metrics to TPD

These should be accessible from another endpoint like /transport-stats or /tp-stats or just /stats to provide the needed metrics for future bandwidth and latency based rewards, as well as potential use for route optimization