Enable non-free ffmpeg on Fedora

Some multimedia codecs are not delivered by default with Fedora Linux, because they are not open source.

These are packaged in the non-free RPM Fusion repos.

sudo dnf install https://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-$(rpm -E %fedora).noarch.rpm

Source: https://docs.fedoraproject.org/en-US/quick-docs/rpmfusion-setup/