Terminate SSL at the load balancer

Implement SSL termination at the load balancer. Because the `rax_clb` module doesn't currently support HTTPS redirection or SSL termination, we'll need to override it with a local module and implement it there.

### Remaining Work

* [x] Acquire the SSL certificate for the prod CLB.
* [x] Create an SSL certificate for the staging CLB.
* [x] Create an enhanced version of the `rax_clb` Ansible module in `script/modules`. This module will add functionality for applying SSL certificates to CLBs to the `rax_clb` module and enabling HTTPS redirection. See http://docs.rackspace.com/sdks/api/python/classpyrax_1_1cloudloadbalancers_1_1CloudLoadBalancerManager.html#a66334c0c0a712389d1c0a3d1e43cbf98 and http://docs.rackspace.com/sdks/api/python/classpyrax_1_1cloudloadbalancers_1_1CloudLoadBalancerManager.html#aad4c90f91195d71b1d99ee598220cb14 on how to do this in pyrax. Note that this will need to be an idempotent operation.
* [x] Submit a PR against the upstream Ansible module.
* [x] Modify `deploy/prod_web.yml` and `deploy/staging_web.yml` to apply self-signed SSL certificates to CLBs.
* [x] Change monitoring checks to test for the 80 to 443 redirect and to verify that the certificate is up to date.
* [x] Load external JavaScript dependencies and Google Fonts from https sources.
* [x] Check for certificates in `deploy/certificates` in `script/deploy`.

Fixes #306.
It actually should be `add_ssl_termination`. `update_ssl_termination` only lets you update [certain attributes](https://github.com/rackspace/pyrax/blob/master/pyrax/cloudloadbalancers.py#L262-L263), not including the key and certificate, while `add` requires you to update everything at once.

While I *could* detect which keys are present in the `ssl_termination` dict and call either add or update as appropriate, that puts us into situations where the module will require different keys depending on the state of the load balancer, which seemed awkward to me.