`incus admin init --preseed` should allow adding a profile to a specific project

The preseed init allows creating both projects and profiles but it does not allow creating a project in a specific project.

For example:

```yaml

profiles:
  - name: myprofile
    config: {}
    project: other_project 

project:
   name: other_project
   features:  {}

```
Should create the `myprofile` profile in the `other_project` project.
The same makes sense for networks & storage.
