Manage redirects of old gh-pages

[mohamed-barakat]

It would be desirable if PackageJanitor could manage redirects of the unneeded gh-pages.

For example

https://homalg-project.github.io/homalg_project/homalg/

could redirect to

https://github.com/homalg-project/homalg_project#readme

while

https://homalg-project.github.io/homalg_project/homalg/README.md
https://homalg-project.github.io/homalg_project/homalg/PackageInfo.g

could remain in place or be part of the download resource.

[zickgraf]

Done for non-meta packages in 9bc5fde.

[mohamed-barakat]

To which repo shall I apply the new PackageJanitor?

[zickgraf]

To any non-meta package.