Add HTTPS (client request) to upstream HTTP-ONLY proxy support

[ohadm2]

Why you need it?

I need to work with a corporate proxy that doesn't support connecting clients via HTTPS directly (the proxy makes the requests for them).

How it could be?

The module will detect that an HTTP-ONLY proxy was setup in the "proxy_connect_address" directive by examining the SCHEMA of the value ("http" or "https" which is currently not supported). If the client will generate an HTTPS request, Nginx will create a new standard http request to its upstream proxy server telling it to make the https request himself (just like a normal http-proxy-aware client).

Other related information

Currently, using a http-only upstream proxy results an "SSL Version Error" error because the upstream proxy gets a direct https request it can't handle. The upstream proxy must be https-aware in order to make a client work with https via this Nginx module and usually that is NOT the case. On top of that, most if not all current web requests are over SSL so this is a real problem....