Add auto log clean up feature

[AndyZ-2021]

After running snapteld for a long time, "snapteld.log" becomes a huge file.
Please add a feature like log4j to roll over the log file, to avoid it fill up the whole disk.

[sandlbn]

These feature should be also extended for plugin log. Also should be good to have possibility to clean/cycle the logs when daemon is restarted.