Help wanted: Merge info from https://wiki.sagemath.org/CategoryHomepage into contributors.xml

[Matthias Koeppe]

The old https://wiki.sagemath.org is a wiki without a community. https://trac.sagemath.org/ticket/33725 proposes to migrate wiki.sagemath.org contents to more suitable places.

https://wiki.sagemath.org/CategoryHomepage lists 58 wiki homepages, most of which are unmaintained. 

Some only contain information on contributions that could be merged into 

https://www.sagemath.org/development-map.html (by editing https://github.com/sagemath/website/blob/master/conf/contributors.xml).

After merging, the pages should be deleted.