Added -n argument to script/logs akin to 'tail -n ...'

[Njinx]

The argument is completely optional, passing positive integer $N to docker-compose -f ... logs --tail $N. --tail is documented here. On omission no functionality is changed.

[mmguero]

actually this is broken, the [: 6 if args.service is not None else -1] needs to be changed to [: 8 if args.service is not None else -1] in order for the services argument to still work.