package RPMs as consolidated tarballs

package RPMs as consolidated tarballs

This results in the following release artifacts being combined:

  * CentOS 7
    * 1 debug RPMs → 1 tarball
    * 22 other RPMs → 1 tarball
  * CentOS 8
    * 20 debug RPMs → 1 tarball
    * 23 other RPMs → 1 tarball
  * Fedora 33
    * 25 debug RPMs → 1 tarball
    * 28 other RPMs → 1 tarball
  * Fedora 34
    * 25 debug RPMs → 1 tarball
    * 28 other RPMs → 1 tarball

This drops the total number of Graphviz release artifacts from 340 to 176. This
is still not below the 50 artifact ceiling we need to hit, but this is
significant progress.

Related to #2147.