(maint) Remove 'puppet-module-dev' gem dependency

(maint) Remove 'puppet-module-dev' gem dependency

In preparation for the Puppet 7 release, the
`puppet-module-posix-dev-r2.7` and `puppet-module-posix-dev-r2.7` gems
had to be removed from `Gemfile` due to the following dependency error:
  `puppet-module-posix-dev-r2.7` depends on
    `puppet_litmus` which depends on
      `bolt` which depends on
        `puppet` which is locked to a version below 7

Also added the needed gems that were lost in the above removal process.