Options for ckan show to hide sections

[HebaruSan]

Motivation

ckan show uses a fairly lengthy hard-coded output format. Some users may wish to only see some parts of it, for example if they're processing the output with other tools.

Changes

Now ckan show has several new options for hiding sections (--with-versions was already there but lacked help text, which is now added):

$ ckan show --help
CKAN 1.30.5+d398f2e236d6
Copyright © 2014-2020

show - Show information about a mod
Usage: ckan show [options] module

  --without-description      Don't show the name, abstract, or description

  --without-module-info      Don't show the version, authors, status license,
                             tags, languages

  --without-relationships    Don't show dependencies or conflicts

  --without-resources        Don't show home page, etc.

  --without-files            Don't show contained files

  --with-versions            Print table of all versions of the mod and their
                             compatible game versions

For example, you can print just the resources like this:

$ _build/ckan.exe show Astrogator --without-files --without-relationships --without-module-info --without-description

Resources:
  Home page:    https://forum.kerbalspaceprogram.com/index.php?/topic/155998-*
  Repository:   https://github.com/HebaruSan/Astrogator
  Bug tracker:  https://github.com/HebaruSan/Astrogator/issues
  Version file: https://raw.githubusercontent.com/HebaruSan/Astrogator/master/Astrogator.version

Fixes #1560.

[DasSkelett]

Works like it should, nice to have 👍