hicolor-icon-theme: new package

This new package provides Freedesktop Hicolor icon theme.

This is the fallback icon theme, which only creates the standard
directory structure for storing icons of third-party applications (i.e.
the ones not available in usual icon themes).

Signed-off-by: Eric Le Bihan <eric.le.bihan.dev@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>