Ability to log the raw request before deserialization and validations

[karthikchejerla]

Its quite useful to log the incoming request payload when using the validator. It standardizes the format and is useful to debug in production environments.

Headers can be logged if configured to do so, to prevent logging API-keys by accident.

PUT /products/1234

{
    "sku" : "1902992",
    "quantity" : 104
}