Rewrite so we don't need to constantly update with every new Fedora
release. This is especially useful when Fedora and Jellyfin release
cycles don't line up.
Version selection is as follows:
* TARGET environment variable, which is currently used already
* Currently running Fedora version
* Hardcoded Fallback version that can be updated occasionally
Simplifies a number of aspects of the RPM build, including moving
.copr/Makefile into the "fedora/" folder (and leaving a symlink),
removing the jellyfin-web build components, and renaming it
jellyfin-server like Debian did.