Allow user to print all logs from a specific date.

**WIP!**

Moved **class logs** to separate file (`lib/shelly/cli/logs.rb`). Splited `shelly logs` into two commands:
* `shelly logs latest` - this is copy of previous `shelly logs` which allows user to print latest logs.
* `shelly logs date [DATE]` - which allows user to print all logs from a specific date.