We increased the PHPStan level from 8 to 9. This lead to some problems when working with query or request parameters.

For example:
```php
$firstName = $request->get('firstName');
```

Because Symfony types `Request::get()` as `mixed` there is no type safety and you have to assert everything manually.

We then learned that we shouldn't use `Request::get()` but use the explicit parameter bag like:
```php
$request->query->get('firstName');
```

This `ParameterBag` is used for `request` and `query`. It contains interesting methods like:
```php
$request->query->getAlpha('firstName') : string;
$request->query->getInt('age') : int;
```

This has the benefit that now the returned value is of a correct type.

Why aren't we being explicit by requiring the parameters and their types in the controller action instead?

Luckily Symfony has a concept called [ValueResolver](https://symfony.com/doc/current/controller/value_resolver.html).

It allows you to do dynamically alter what is injected into a controller action.

So in this PR, we introduces 2 new attributes: `#[QueryParameter]` and `#[RequestParameter]` that
can be used in controller arguments.

It allows you to define which parameters your controller is using and which type they should be. For example:

```php
#[Route(path: '/', name: 'admin_dashboard')]
public function indexAction(
  #[QueryParameter]
  array $ids,
  #[QueryParameter]
  string $firstName,
  #[QueryParameter]
  bool $required,
  #[QueryParameter]
  int $age,
  #[QueryParameter]
  string $category = '',
  #[QueryParameter]
  ?string $theme = null,
)
```

When requesting `/?ids[]=1&ids[]=2&firstName=Ruud&required=3&age=123` you'll get:
```
$ids = ['1', '2']
$firstName = "Ruud"
$required = false
$age = 123
$category = ''
$theme = null
```

It even supports variadic arguments like this:
```php
#[Route(path: '/', name: 'admin_dashboard')]
public function indexAction(
  #[QueryParameter]
  string ...$ids,
)
```

When requesting `/?ids[]=111&ids[]=222` the `$ids` argument will have an array with values ['111','222'].

Unit testing the controller now also becomes a bit easier, as you only have to pass the required parameters instead of constructing the `Request` object.