add field to package info for link to upstream repository.

[lolbinarycat]

i've already opened NixOS/nixpkgs#294347 to add support for this, although it should also be possible to recreate the logic without that.

if both the homepage and repository fields were set to the same value, only the repository should be shown.

[lolbinarycat]

i could probably help with making the required changes to the backend, since i know rust, but i don't really know elm or javascript, so i can't help much with the frontend.

[lolbinarycat]

nixpkgs pr has been merged, i'm gonna take a shot at this, although i'm not sure if i can do the frontend work, since i don't know elm.

[iFreilicht]

@lolbinarycat Thank you for your work on this! I'd be happy to try my hand at the frontend part. I haven't really used Elm yet, but read a lot about it recently and would like to apply some of that.

[lolbinarycat]

i opened a basic PR at #751, i would be very grateful if anyone can help with testing and improvements.