Add option to set 'use-old-size-bar' via command line

[artyl]

Please, add the ability to set 'use-old-size-bar' via the command line.
The absence of a command-line option for 'use-old-size-bar' is very inconvenient for me because one of the use cases for me is portable, and on many servers without using 'use-old-size-bar' I get something like this #255 (comment)
The option can be named --use-old-size-bar or --no-unicode and -u
Thank you for your gdu

[artyl]

Awesome, looking forward to the release to give it a try.