URLchecker fixes for the partners pages

Folks,

There are a whole lot of pages which fail the URLchecker for https or because
companies etc. have moved.

A lot of these are common - looking at, for example, 
https://www.master.debian.org/build-logs/urlcheck/partners.en - there's
a lot of entries which would be fixed by single edits.

This _shouldn't_ have effects on translated pages - would anybody object
if I started the process of clearing the errors - to include the pages 
identified by year?

There's also the point that a lot of CD and image mirrors have also 
disappeared over the years and could do with tidying up.

All advice gratefully received

All the very best,

Andy Cater