Remove PPA from bootstrap

I don't think this project uses any packages from this repo and we're not
subsequently managing it in Puppet.
Amend disk size from 50gb to 300gb

Given that we are required to keep thirty days of back-ups, and that each of
these is approximately 5gb to 6gb in size, we should re-size /srv/backup-disk
appropriately.
Merge pull request #30 from alphagov/resize-disks

Amend disk size from 50gb to 300gb
Pin to Puppet 3.4 and Facter 1.7

So that we are consistently using the same version (which is at the time of
writing latest stable and what we use on GOV.UK) instead of picking the
latest from the PuppetLabs repo at provisioning time.

This doesn't address managing the version of Puppet for existing machines.
We probably want to use alphagov/puppet-puppet
Merge pull request #27 from alphagov/pin_puppet_facter_versions

Pin to Puppet 3.4 and Facter 1.7
Merge pull request #28 from alphagov/remove_ppa

Remove PPA from bootstrap
Don't write Fog credentials to disk

Read fog credentials directly from environment variables rather than writing
them to disk. This is generally more secure, but also addresses a race
condition (of sorts) whereby the credential file will be left if
`vcloud-launch` were to exit with a non-zero status.

All existing environment variable names have been preserved so that no
changes to the existing Jenkins job is necessary.

Borrowed from gds/pp-pilotis - should be replaced with an authentication
token when [#68989754] provides a generic tool to do so.
Merge pull request #31 from alphagov/dont_write_fog_creds_to_disk

Don't write Fog credentials to disk
Amend SSH key

I have a new Mac.
Merge pull request #34 from alphagov/amend-sshkey

Amend SSH key
Bulk out README.md
Expand on alternative Vagrant providers
No longer explicitly define Puppet versions

By not explicitly defining Puppet versions in `.travis.yml`, when Travis
runs, it will run against the latest version in the repository's Gemfile.

This means that when we upgrade Puppet on this box, the integration tests
should update automagically.
Amend README.md to reflect reality
Add Cal Paterson

Cal needs to be able to get this machine. Adding his key.
Merge pull request #37 from alphagov/travis-futureproofing

No longer explicitly define Puppet versions
Merge pull request #38 from alphagov/add-calpaterson

Add Cal Paterson
Allow SSH from Memset back-up box
Merge pull request #40 from alphagov/ssh-backup0provider1

Allow SSH from Memset back-up box
Install `pdxcat/nrpe` module

The `pdxcat/nrpe` module allows us to configure NRPE on client machines. It was
chosen for a number of reasons:

- it does not require any dependencies: a lot of other modules on the Puppet
  Forge did, and bringing these in to the mix would then add additional layers
  of complication which I did not wish to introduce

- re-using other people's code is a [Good
  Thing(TM)](https://gds.blog.gov.uk/2012/10/12/coding-in-the-open/) to continue
  our strategy of coding in the open

This commit adds the `pdxcat/nrpe` module to our Puppetfile (and the
Puppetfile.lock using librarian-puppet).