[test] SSL config amulet test

[nicopace]

Implement a test to ensure the ssl configs work as expected.
To do this, we should test in 3 different situations:
* as a Reverseproxy
* as a Balancer
* as a website-cache
To do this, create a self signed certificate, and provide it to an example of them three.
Also, try the SELFSIGNED attribute.

Then, the requests library can be used to do SSL Pinning with the created self signed certificate, and with the charms's created certificate. It is documented here: http://docs.python-requests.org/en/latest/user/advanced/#ssl-cert-verification