Feature: automatically create docs for kwctl commands and flags

[viccuad]

OpenSSF best practices asks us to document our API. As cli tool, that means kwctl commands and flags.

Acceptance criteria

Add a new kwctl docs, that outputs a Markdown or similar file with the docs for all our clap commands and flags. This can be achieved with clap-markdown.

On release, and after building kwctl, run kwctl docs and ship the resulting markdown file as GH artifact in the GH release.

Use updatecli to consume the new markdown doc file from the GH release, and automate its inclusion into the reference section of kubewarden/docs.