httpcfg doesn't support intermediate certificates

[blastagator]

Let's Encrypt has exploded in popularity. However, mono's implementation of httpcfg still does not support intermediate certificates. This makes it impossible to use LE certs with mono.

I don't believe this is a bug, per se, as the behavior is well documented, but this would be a nice feature to update.

In testing I could freely change between my self-signed cert (which worked fine every time) and attempting to load the full LE chain, which loaded but failed to function every time.