Move relevant files from pp-development

Moved files required for development setup from
https://github.com/alphagov/pp-development
Update to make sense in pp-puppet context

Updated the instructions so they can be run from pp-puppet rather than
pp-deployment, including additional hosts file step that seems to be
required when using pp-puppet
Merge pull request #403 from alphagov/move-pp-development

Attempt to move relevant files from pp-development