Draft: [Servers] Updating webkitgtk to 6.0

In November, Fedora removed webkit2gtk5.0 replacing it with webkitgtk6.0. Unfortunately, because we forgot to add that package as a dependency in Komikku, we were not contacted by the Fedora webkitgtk maintainers, and Komikku broke in Fedora Rawhide (it fails to open).

Unfortunately, webkitgtk6.0 is still very young, as such, it does not seem to be available in most repositories yet, so this pull request should definitely not be pushed yet. I'm just sending it here yet just in case some other maintainer run into the same issue.

Also, this patch seems to break japscan and readcomiconline. I'm still investigating the issue (thus the Draft status).