Improve summary

[piotr-yuxuan]

• It should be possible to (recursively) hide some options or nested map from the summary.
• :description, as expected, should be the actual description as per malli convention. However it should be give part of the description and leave malli-cli generate standard description parts about enum possible (parsed) values, non-idempotency (including difference between long and short value), env and var lookup.
• Include a synopsis in the summary.
• Allow the user to provide a max width with a default to 80, or allow to disable it.
• Add simple colouring and try to integrate with some shell conventions here.