I'd like all my Controller action routes in the namespace 'App\Controller\Api' to have the prefix '/api'. I also want to use annotations inside the controllers to set the rest of the route.

In Symfony 3 this was done by editing 'config/routing.yml':

```
app:
    resource: '@AppBundle/Controller/Api'
    type: annotation
    prefix: /api

```

How can I do this in Symfony 4? Do I need to make a bundle? Which config file would I use since I don't have a 'config/routing.yml'?