dnf has replaced yum on Fedora and CentOS. On modern versions of Fedora,
you have to install an extra package to get the old name working, so
avoid that inconvenience and use dnf directly.
Closes#181
To align build system with scylla main repo, adding relocatable package
support.
On scylla-jmx, we don't provide libraries and linker since it's Java
program, just contains .jar file and dist/ directory.