Link to fd.o dependency reports

[TheEvilSkeleton]

At the moment, Flatpak docs don't really provide an easy way to get to the fd.o SDK Release Content. However, the Release Content page is tedious and difficult to find. I opened https://gitlab.com/freedesktop-sdk/freedesktop-sdk/-/issues/1476 to improve readability and accessibility improvements.

We should also get KDE, GNOME and elementary's reports too, to facilitate the process of finding dependencies that these runtimes and SDKs offer.

[bbhtt]

KDE cannot generate a dependency report as they build it on Flathub infra with flatpak-builder.

GNOME doesn't have a release content page but since last two months has started producing a CVE page.

At the moment the only common ground is looking at manifest.json