Add MapEntity support to breadcrumbs

[bjorvack]

Add support for the #[MapEntity] attribute in routes to map the correct parameter to fetch the entity

example:

url https://app.wip/file/DPLA167

    #[Route('/file/{file}', name: 'file', requirements: ['file' => '^DPLA\d+'])]
    #[Breadcrumb('{file.number}', parent: ['name' => 'file_overview'])]
    public function __invoke(
        #[MapEntity(mapping: ['file' => 'number'])] File $file,
    ): Response {
        ...
    }