infozip: rename to zip

We currently have a package named "infozip" for Info-Zip's Zip.

With the upcoming addition of a package the Info-Zip's UnZip the name
is becoming ambiguous. Rename it to the more specific name "zip".

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Cc: Romain Naour <romain.naour@openwide.fr>
Cc: Jan Pedersen <jp@jp-embedded.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Reviewed-by: Romain Naour <romain.naour@openwide.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>