package/pkg-utils: show-info: virtual packages can also install things

package/pkg-utils: show-info: virtual packages can also install things

Although most virtual packages do not install anything, some of them
do. For example, the virtual package 'toolchain' does tweak the musl
headers during a post staging hook.

So, it makes sense for "show-info" to report if a virtual package has
its target, staging and/or image installation steps enabled or not.

This commit changes show-info to report the type of install steps for
virtual packages too, which means for all packages.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Vadim Kochan <vadim4j@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: eeppeliteloop@gmail.com
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>