[DX] Generation progress

[Korbeil]

It would be awesome to have a detail about generation progress and list of generated classes by group (Model / Normalizer / Endpoint / ...)

Exemple output:

Generating for schema `path/to/schema.yaml`

✔️ Guessing
✔️ Generating

Output: `path/to/generated/`

 * 12 Models
 * 12+2 Normalizers
 * 7 Endpoints

Done in 7 seconds