try-runtime-cli: polish output

[liamaharon]

Motivation

The try-runtime cli output/progress indicators is a little rough around the edges.

Request

Logs, progress indicators, error handling, and hints to the user when they do something wrong could all do with some revision and TLC.

Promising progress bar library: https://github.com/console-rs/indicatif

[liamaharon]

Moved to paritytech/try-runtime-cli#13