Permit HttpFoundation\Request class override

This PR solves #7453. Requests are now created through a `RequestFactoryInterface`.
The default factory just call `::create()` method on the request class which can be configured with `request_class` parameter under `framework` section.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | I don't know
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7453