Keep Host header intact

[kichik]

Set the Host header to match that of the original request. This allows to more easily handle the mirrored traffic, especially if the source handles multiple virtual hosts.

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[SimonePomata]

The original Host header is added to the X-Forwarded-Host header. The current behaviour is expected by some applications.
Anyway, I also see the use case for keeping the orignial Host header.

My proposal is to add a KeepOriginalHostHeader parameter to the CloudFormation template, which is false by default (for backwards compatibility), but can also be set to true.
@kichik any thoughts?

[kichik]

Yeah makes total sense. I went ahead and added the parameter as requested.

[SimonePomata]

thanks @kichik! I will review and merge in the coming days.