Implement back off for logs streaming

[philnash]

Currently the logs command with --tail option keeps making requests to the logs endpoint at the rate of 1 request per second. There is also the ability to choose the period, though that is not currently exposed in CLI flags.

To lower the pressure on the logs endpoint, we propose to back off requests if no new logs are returned for a period of time.

Initial ideas were to reduce the period if no new logs are returned for 10 periods. After that we can double the period and wait 10 more periods before backing off again.

Once a new log is discovered and logged, the period should return to the initial period.

Each time we back off we should log the new period so that developers can see what is happening and either stop streaming, or restart the command because they expect to see new logs again.