Improve user experience with on-standard http -> https redirect

[spalger]

When the Kibana server is setup to use SSL it tries to redirect HTTP requests so they will automatically start using HTTPS. This has worked great, and I find it really helpful, but this is very non-standard behavior that has tripped up several users trying to setup Kibana behind a proxy. On top of that, the httppolygot library (which provides this behavior) is sort of magical and we would like to remove it.

A normal webpage would listen for http requests on port 80, and https requests on port 443, then redirect people from one to the other, but fail to accept requests for the incorrect protocol at each port. This works well on the web because web browsers automatically use port 80 or 443 based on the protocol, but is not as smooth when the port is specified explicitly (as we suggest doing).

• Should we add setting to disable the redirect?
• Should we remove the redirect completely?
• Should we support different http and https ports that redirect between each other?

USERS: Are you relying on the current http -> https redirect?

[trevan]

I only use it during development but even then, I usually have ssl disabled. I deploy Kibana behind an nginx proxy to handle the ssl connections.

[spalger]

Thanks @trevan. If other users want to speak up please see #10181