* Add binary encoding logic into ActionDispatch::Request::Utils

Moving the logic to set binary encoding into ActionDispatch::Request::Utils
will allow us to encode from GET and POST in ActionDispatch::Request.

* Refactor binary encoding logic

- Move binary encoding calls into GET, POST and path_parameters
- Remove binary encoding from ActionDispatch::Http::Request
- This way, we only raise an invalid encoding exception if the controller is not requesting
parameters in binary encoding

* Check if encoding is valid in ActionDispatch::Request#POST and raise BadRequest if invalid

* Fix multipart_params_test that has binary-encoded params containing invalid UTF-8 characters

* Address PR comments

* Pass action and controller to Request::Utils.set_binary_encoding

[Rafael Mendonça França + Adrianna Chang]