Ability to redirect http to https in styx

The ability is implemented in two things

1) Add the ability to configure http and https mappings separately
2) Add a blanket redirect rule that can be used to redirect traffic anywhere

@kentquirk @jh-bate give this a once over when you have a chance pls.  It's for

https://trello.com/c/i1tP05qa/135-notes-tidepool-io-needs-http-https-redirects