RCE via the DecompressedArchiveSizeValidator and Project BulkImports (behind feature flag)

The `DecompressedArchiveSizeValidator` is used to check the size of a archive before extracting it:

      def command
        "gzip -dc #{@archive_path} | wc -c"
      end

   def validate
        pgrp = nil
        valid_archive = true

        Timeout.timeout(TIMEOUT_LIMIT) do
          stdin, stdout, stderr, wait_thr = Open3.popen3(command, pgroup: true)
          stdin.close