support/scripts/pkg-stats-new: add -n and -p options

support/scripts/pkg-stats-new: add -n and -p options

This commit adds the following options to the pkg-stats-new script:

 -n, to specify a number of packages to parse instead of all packages

 -p, to specify a list of packages (comma-separated) to parse instead
     of all packages

These options are basically only useful when debugging/developing
this script, but they are very useful, because the script is rather
slow to run completely with all 2000+ packages, especially once
upstream versions will be fetched from release-monitoring.org.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Reviewed-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>