Add node['firewall']['configuration'] for adjusting /etc/default/ufw

[rchekaluk]

Supports a new attribute node['firewall']['configuration'] as a hash containing arbitrary ufw settings to be assigned in /etc/default/ufw. The recipe is idempotent and will add new settings to /etc/default/ufw, but edit settings if they exist already.

Example usage for using ufw with Docker:

    firewall_rules = {
      :firewall => {
        :configuration => {
          'DEFAULT_FORWARD_POLICY' => 'ACCEPT',
        },
        :rules => [
          {"docker_remote_api" => { "port" => "2375" } },
        ]
      }
    }

[smurawski]

Since this is a bash resource (or any of the execute resources really), you need to make sure either in your code block or in a guard that you are only modifying the file when it is needed. Especially in this case, where you are notifying a service to restart after the edits. If chef-client is run on a schedule that would continually edit the firewall file and restart the service.

[rchekaluk]

Done, guard added per feedback. Also includes additional strengthening of grep and sed match patterns, and a condition to prevent editing if key is blank.

[tas50]

I'm going to close this out at this point since master has diverged to the point where it can no longer be merged. If you want to rebase the changes against master it would be great to have this change in this cookbook.