Fix SSL configuration

This is an attempt to augment and extend the SSL features of haproxy on top of the default recipe of haproxy. This adds two site specific attributes to account for these features.

The basic issues that are being fixed in this PR are:

1. Fix backend SSL termination (upstream is broken)
2. Add ability to enable frontend SSL but still use http for the backend
This is kind of a scary way to do this because if Chef ever changes resources to merge or conflict, this will massively break. A slightly better way is to do the following:

```ruby
chef_gem 'chef-rewind'
require 'chef/rewind'

include_recipe 'haproxy::default'

rewind haproxy_lb 'https'
rewind haproxy_lb 'servers-https'

# Call haproxy_lb resources here
```

This has the advantage of entirely undoing the resources in <code>haproxy</code> rather than relying on an odd quirk.