template: Add Plamo Linux template

This template allows to create Plamo Linux container on Plamo
Linux. Plamo Linux is Japanese distribution, which is originally based
on Slackware Linux.

Signed-off-by: KATOH Yasufumi <karma@jazz.email.ne.jp>
Signed-off-by: TAMUKI Shoichi <tamuki@linet.gr.jp>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>