Part of a wider housekeeping effort on the packages repository.

Signed-off-by: Alberto Bursi <alberto.bursi@outlook.it>

I needed also sgdisk (script-friendly) and while I was at it I added also
cgdisk (uses ncurses interface), all as separate packages.
re-arranged the package folder and set /usr/sbin for install folder
as most tools seem to go in there and not in /sbin.

Signed-off-by: Alberto Bursi <alberto.bursi@outlook.it>