Refactor server recipe to use Pebble server

[ramereth]

This is a major refactor for the server recipe which is used for testing only. This migrates us away from the clunky and slow Boulder server to the lightweight and nimble Pebble server [1]. This largely uses the method that the upstream acme cookbook [2] uses for it's own testing however with a few modifications.

Namely, instead of compiling the pebble binary during an initial converge, pull in a pre-compiled binary that exists on our own servers. This means we do not need to pull in any additional build dependencies to get this going. While Pebble does not require the use of a local DNS server for validation purposes, I decided to keep this in there to help with integration testing with InSpec.

This pulls in the same test cookbook and tests that the osl-letsencrypt-boulder-server cookbook had for its setup with a few minor modifications.

Some changes to keep in mind:

• Attributes for node['boulder']['host_aliases'] should be renamed to node['osl-acme']['pebble']['host_aliases']
• Setting node['acme']['dir'] in .kitchen.yml is no longer required as it's set in the server recipe by default.
• Support for was re-added CentOS 6 which required creating a proper init script.

[1] https://github.com/letsencrypt/pebble [2] https://github.com/schubergphilis/chef-acme/blob/master/test/fixtures/cookbooks/acme_server/recipes/default.rb

[ramereth]

Refactor server recipe to use Pebble server

[ramereth]

!bump major *

[osuosl-manatee]

Jenkins has merged this PR into master and has automatically performed a major-level version bump to v3.0.0. Have a nice day!