(Straightly related with #33)

Context

A really very-well feature for Killgrave would be to be able to create "responses" (configuration) itself on-the-fly.

The idea is to let the user to configure only the imposter's request and then let Killgrave do the magic: fill the response section (within imposter) by going to the "real" implementation and getting the response.

Proposed implementation

That feature could be implemented on a two-steps development:

• Firstly, developing a module responsible of that magic (able to create configuration from an HTTP response).
• Secondly, allowing a new choice (record) for the proxy_server's mode configuration that would allow the user to enable that recording (just for the missing endpoints).