Logging / Channel padding delay

Logging / Channel padding delay

Reduce the amount of messages being logged related to
channel padding delay when log level is "notice".
Log the channel padding delay as "info" as soon as the
delay occurs. Log "notice" on each heartbeat only
containing the average channel padding delay and the
amount of delays (that exceeded the allowed time window)
occurring between heartbeats or, if first heartbeat
since startup, between startup and heartbeat.