True noarch Erlang packages

Prior to this release, Erlang packages were being installed into %{_libdir}/erlang/lib (which resolves to, for example, /usr/lib64/erlang/lib on x86_64). This makes them compiled "archful" despite most of them being Erlang and therefore noarch. Therefore they must be built and stored separately for each architecture and causes unnecessarily long build times and uses additional storage in Koji and on distribution mirrors.

The Erlang VM that ships in Fedora 29 is modified to also search %{_datadir}/erlang/lib (which resolves to, for example, /usr/share/erlang/lib on x86_64) in addition to the previously used directory when searching for dependencies, and build macros are updated to automatically use the new path to install noarch packages. "Archful" packages will continue to install in the old directory.