[WIP] Create a controller argument resolver to replace the param converter

[mbabker]

This is an attempt to get the ball rolling at deprecating the param converter integration in favor of the framework's native argument resolvers. It's untested, it does not have 100% feature parity with the existing implementation (some of that being by design since the two systems are different), and it's kind of a Frankenbeast trying to deal with Symfony 5.4 support, but here we are.

Note, this will only support PHP 8. Considering the Sensio bundle works fine on Symfony 5.4 and Symfony 6 requires PHP 8, as well as argument resolvers having only ever supported PHP 8 attributes (#[CurrentUser] exists in Symfony 5.4 but has no @Annotation declaration), I personally don't see that as an issue.

The attribute and resolver design try to take inspiration from the framework's #[MapRequestPayload] attribute and RequestPayloadValueResolver while only re-implementing the functionality in the existing RequestBodyParamConverter. So the validator integration is still opt-in (whereas in the framework if the validator's injected it is always used), and this bundle's serializer bridge continues to be used.

Things that have changed in the workflow:

• No more "is optional" style conditional aborts, all errors now throw
• Since an argument value resolver can't provide two separate arguments (the resolver itself enforces only providing one value unless working with a variadic argument), and some of the order of operations logic here is already crazy, a validation error now throws its HTTP exception instead of adding the violation list as another argument for the controller
• The deserialized payload isn't written to the request attributes

Things that still need to be done if this is usable:

• Tests
• Wire services in as appropriate
• Adapt the bundle config?