Filter based on multiple inrepo parameters

[jcgruenhage]

My usecase: I'd like to see outdated packages for voidlinux written in rust, because most of the software I maintain packages for is written in rust. Therefore, I can best help with that software.

Proposed solution: Filtering based on multiple repos (so software that is present in multiple repos, so that in my case only software both in void and in crates.io are displayed. This will not 100% solve my problem, but it will do so for a lot of the packages.

Other possible solutions: Filtering based on build dependencies, but I don't think repology is tracking build dependencies at the moment. With that, I could filter for outdated packages in void that depend on rustc.

[jedahan]

This would also help in searching for packages (not) in "main repo" or "community repo", which helps see a bigger picture of a distros comprehensiveness.