Regex to pomsky converter

[Aloso]

Is your feature request related to a problem? Please describe.

If you have lots of regexes, rewriting them in pomsky is currently an annoying, elaborate task.

Describe the solution you'd like

A tool, part of pomsky-bin, that converts a regex to a pomsky expression. This tool should understand all the supported regex flavors and return a correct pomsky expression with the exact same behavior, formatted and indented nicely. It should be as idiomatic as possible, although it shouldn't introduce variables or use numeric ranges.