Preserve host subscription entitlements

- Include /run/secrets in buildah usage
- Eliminate using chroot except req type "source"
  - All of the chroot supportig code moves into the
   'source' req section, a lot of code
  - The "source" type needs chroot because src installs often have chdir
    in some commands and that pwd is not preserved when fedding it
    to 'buildah run'.
  - There may be another req type which still needs chroot method,
    perhaps 'manual'?