Display a link to the Arch/AUR package page in the info area.

I think it would be nice if pamac would display a link to the website of the arch package. The URLs seems to be https://www.archlinux.org/packages/<repository>/<arch>/<pkg_name>/ and https://aur.archlinux.org/packages/<pkg_name>/.

It doesn't work for local packages though because I don't know how to retrieve the repository name for these packages.