Use nordselect-bash

[avorima]

This repo implements server selection using only bash: https://github.com/j-piecuch/nordselect-bash. The URL that is used here to select a server seems to have a 1 hour rate limit, so it's not that ideal. The only thing that's missing from nordselect-bash is the server ping, but it's already present here. I would propose to either make it a required dependency or simply include it here since it's also MIT. Either way it obsoletes the python code.