File logging

[OpenBagTwo]

GIVEN Alex or M.A.R.I.L.L.A is running EnderChest sync operations regularly

WHEN they go into their EnderChest folder inside their $MINECRAFT_ROOT

THEN they can go into a folder named .logs (hidden on POSIX systems) and view plaintext logs of all recent EnderChest operations, captured by default at the DEBUG level and above

SO that they can find out when a particular file was last synced or otherwise debug some odd behavior (e.g. #127)

Notes

• The .logs folder should not be synced by default.
  Python has built-in support for rotating log files.
• A lot of the logging behavior (such as the logging level and the log retention policy) should be controllable via config

[OpenBagTwo]

Blocked by #136