Build endpoint CreateModelVersion

We need a new endpoint named CreateModelVersion, in the new training API group.

It will be exposed as POST on the route /api/v1/model/<model_id>/versions

This endpoint will allow ant contributor or admin of the Model to create a new ModelVersion, by specifying:

• hash (required)
• size (required)
• parent_id (optional)
• description (optional)
• tag (optional)
• configuration (optional)

The creation serializer MUST provide in return a pre-signed s3_put_url on the dedicated bucket for models (the path is {model_version.id}.zstd