* guix/scripts/package.scm (list-installed): New procedure.
* guix/scripts/home.scm (%options, show-help): Add '--list-installed'.
(process-command): For 'describe' and 'list-generations', honor the
'list-installed option.
(display-home-environment-generation): Add #:list-installed-regex and
honor it.
(list-generations): Likewise.
* guix/scripts/utils.scm (pretty-print-table): New argument "left-pad".
* doc/guix.texi (Invoking Guix Home): Add information and example for
--list-installed flag.
Co-authored-by: Ludovic Courtès <ludo@gnu.org>
55725724dd