Add ability to extend timeout for delivery_test_kitchen EC2

[TonyLovesDevOps]

We use heavily the delivery_test_kitchen functionality to run functional tests as part of the delivery pipeline, by calling this within .delivery/build-cookbook/recipes/functional.rb:

if node['delivery']['change']['stage'] == 'acceptance'
  delivery_test_kitchen 'functional' do
    yaml '.kitchen.ec2.yml'
    driver 'ec2'
    action [:converge, :verify, :destroy]
  end
end

This works great! However, several of our cookbooks take over 10 minutes to complete (especially ones that e.g. install a lot of packages as part of their converge), and that fails the stage and the project can't be delivered, even if the converge/verify would have succeeded eventually.

There doesn't appear to be a way to easily extend the timeout. For now, we work around this by monkey patching in each cookbook that requires the timeout to be extended:

# inside .delivery/build-cookbook/libraries/extend_timeout.rb
# Monkeypatch TestKitchen class to override default (600s) timeout to 1800s
class ::DeliverySugar::TestKitchen
  #
  # Run test kitchen action
  #
  def run(action)
    Chef::Log.warn "overriding kitchen run action"
    prepare_kitchen
    shell_out!(
      "kitchen #{action} #{suite} #{@options}",
      cwd: @repo_path,
      env: @environment.merge!('KITCHEN_YAML' => kitchen_yaml_file),
      live_stream: STDOUT,
      timeout: 1800
    )
  end
end

I'd love to see a configurabletimeout parameter added to delivery_test_kitchen. I just don't have the time right now to make a PR, so I'm making an issue instead.