Remove load_nodes.rb
Remove load_nodes.rb

This was added in July 2014, and used by the accompanying
vagrant-govuk/Vagrantfile:
https://github.com/alphagov/govuk-puppet/commit/acc23e160d418b8976b052583414844bf6482e87

That file was moved to root-level 'Vagrantfile' in Feb 2016:
https://github.com/alphagov/govuk-puppet/blob/d578a5886bd4e5135dfd109842d7142e5e68ae8e/Vagrantfile

Then it was deleted in June 2020:
https://github.com/alphagov/govuk-puppet/commit/c2d47d22a4913caa7036dc61bafaa9ea9bc7f308

The 'load_nodes' dependency should have been deleted at the same
time, but got left behind. Checking out the repo at that commit
(`git branch -b tmp c2d47d22a4913caa7036dc61bafaa9ea9bc7f308`) and
then searching in the govuk-puppet directory shows nothing else
was calling the load_nodes code at that point.

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