Add rudimentary rsync storage backend
Add rudimentary rsync storage backend

- We might want to use this script to copy files somewhere different
  from S3.

- The rsync script bits may need to include encryption/this version is
  unsuitable for sensitive data

- This assumes the executing user has suitable SSH pubkey authentication in place

solo @schmie

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet