This patch adds the Cliff Sphinx Extension support for auto documenting
the `validation` Command Line Interface. It also standardizes the
`metavar` description for all the --group, --category and --product
arguments by using <group_id>, <category_id> and <product_id>.
Moreover, it removes usage example(s) in the arguments helpers which are often
duplicated with the `metavar`.
Change-Id: I3009337e8afadd705bbee5b89d9022c78093cdc8
Signed-off-by: Gael Chamoulaud (Strider) <gchamoul@redhat.com>
e4b5dc3ea7