Software changelog shouldn't be in RPM spec changelog

According to the generally accepted rules of RPM creation, the RPM specfile's changelog is meant to be a changelog regarding the RPM itself, not the software being packaged. So, I've moved the software changelog to a CHANGES file. This also gets us rid of the changelog on the upcoming version, so we don't need a 'tba' in the next version's changelog (in the RPM), which would stop the RPM from being built.