Consider switching argument handling to use picocli

[sleberknight]

Picocli is a one-file framework for creating Java command line applications with almost zero code. It supports a variety of command line syntax styles including POSIX, GNU, MS-DOS and more. It generates highly customizable usage help messages that use ANSI colors and styles to contrast important elements and reduce the cognitive load on the user.

https://picocli.info/

It does a lot more too, such as tab completion, ANSI colors.

As another alternative, we could use argeparse4j, which is what Dropwizard uses.

References:

• Quick Quide
• User Manual
• GitHub repository

[sleberknight]

This change (probably to picocli) will be made in #129