Prerelease 6.5.1-pre1

#### Added
- Added a comment to the sample EL8 kickstart file to describe changes
  needed if booting in UEFI mode.
- Increased the minimum puppet-agent version required to 6.22.1.

#### Changed
- Update unpack DVD to extract the SIMP repo into
  `<destination dir>/SIMP/<os family>/<os version>/` and create the link to the
  major version if it is requested.
- Changed shebang in convert_to_inetorg.rb to use Puppet's Ruby instead
  of system Ruby.

#### Removed
- Removed `upgrade_simp_6.0.0_to_6.1.0` script