Support for non-LE SSL Certs and non-Route53 DNS providers

[bcongdon]

Description

• Exposes certificate, certificate_key, and certificate_chain in the README documentation. (Should these be renamed to *_file for clarity?)
• Adds using_route53 option. Allows disabling Route53 record changes when doing a certify
• Adds a sanity test for the non-Route53 method of certifying

GitHub Issues

#517 - Adds the ability to bypass the Route53 DNS record updates, allowing both custom certs and DNS
#401 - This functionality already exists, but wasn't exposed anywhere (to my knowledge) in the documentation

[Miserlou]

Oh baby! Hopefully I can get to reviewing this today.

Suggest we move using_route53 to use_route53 to be consistent, or move it to route53_enabled to be.. consistent. Requesting input on that one.

[coveralls]

Coverage decreased (-0.02%) to 81.335% when pulling c857d00 on bcongdon:manual-cert into 9c58099 on Miserlou:master.

[Miserlou]

Bumping this one, I'd like to get this merged sometime soon.

[bcongdon]

I'm onboard with the config var rename. Changed it to route53_enabled to match apigateway_enabled

[coveralls]

Coverage decreased (-0.4%) to 80.966% when pulling a20ad36 on bcongdon:manual-cert into 9c58099 on Miserlou:master.

[Miserlou]

Let's do it!