Set Django request object through a server method call

[mizvyt]

Slight improvement to the way Django request object was handled previously.
This will simply let the backend set the request object to the server class instance, and have it consumed inside the server class.

This solves the issue with:

• Dubious use of headers
• Use of _-prefixed method from an internal library

This doesn't solve the issue of:

• Passing duplicate data, as uri, http_method, body, headers are still passed along with the request