Tools/scripts: Add report-outdated-for-maintainer.py

report-outdated-for-maintainer.py checks Repology and GitHub
and produces a categorized report of outdated ports.

It produces a better report than Repology produces:
it produces 3 tables:

• Majorly outdated ports
• Moderately outdated ports
• Slightly outdated ports

and it sorts outdated ports by how much are they outdated.

There are still minor bugs. This is WIP.