Change base image from `fedora-distrobox`

[zelikos]

davincibox is currently based on uBlue's fedora-distrobox, but that repository is now archived as the contents were moved to their toolboxes repo.

We could simply change the base image over to their fedora-toolbox image, but it might also be worth considering just using the upstream Fedora toolbox image instead. uBlue's fedora-toolbox includes a lot of extras that may not be necessary for davincibox (see the Containerfile); one big consideration being whether RPMFusion is necessary or not.