Remove the request from parameter converters

Problem/Motivation

Currently the current $request is passed into parameter converters convert() method. However, not one in core actually depends on the request.

The dependency of the paramater converter service on the request is one of the reasons why it is currently necessary to prepare a fake request when executing access-checks on arbitrary routes.

Proposed resolution

Remove the request from parameter converters and get one step closer to removing the fake-request hack in AccessManager::checkNamedRoute() as well as the RequestHelper::duplicate() method.

Remaining tasks

User interface changes

API changes

Before: ParamConverterInterface::convert($value, $definition, $name, array $defaults, Request $request)
After: ParamConverterInterface::convert($value, $definition, $name, array $defaults)