[DX][HttpFoundation] Add RequestInterface

[amikheychik]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	yes
Deprecations?	no
Tests pass?	yes
Fixed tickets	no
License	MIT
Doc PR	no

Currently few methods in the HttpFoundation component are using Request class in the type hints. It's very inconvenient for a developer if he want to use his own class for the HTTP request object without extending the Symfony's original class (in that case Response class, for example is not possible to use).

Added interface only exposes methods that are required for the code, that worked with the Request class to have all the information it had originally. (I've checked only usage inside HttpFoundation component)

[ghost]

I wonder if this is worth doing now or waiting until PSR-7 is completed.

[aitboudad]

#10389 (comment)

[Tobion]

I think this can be closed. I don't think we are going to create interfaces of the request/response in the current state as it's not clean enough, see #6406
If there will be interfaces, it's more likely going in the direction of PSR-7.