Add SELinux policy module for rpm to support rpmdb in /usr
    
    In order for RPM to work properly with the rpmdb in /usr, we need
    the new directory to be configured correctly in the SELinux policy.
    
    This cherry-picks commits from Fedora's SELinux policy to implement
    that as an independent overlay module.
    
    References:
    
    * https://github.com/fedora-selinux/selinux-policy/commit/5f69c12c67da7ef8783f5180f743180d564f4e96
    * https://github.com/fedora-selinux/selinux-policy/commit/d99577b16e8be3de46528fa81133efd2dd40b7c5