Consider using EmbeddedComposer for packages that are using admin

[moufmouf]

Mouf comes with 2 sets of dependencies (and therefore 2 composer files).
One for the app
One for the admin

When adding a package to the composer.json file of the app, it would be great to be able to add at the same time a dependency dedicated to the admin.

For instance, right now, if we install a DB connection driver in the app, the DB connection driver might come with a controller for the admin side that requires evolugrid support.

The idea is:

In the composer.json file of a package loaded in the "app" context, we could put:

{
  extra: {
    mouf: {
      require-admin: {
        "mouf/evolugrid" : "~1.0"
      }
    }
  }
}

The admin side should read those "require-admin" sections and could load them, thanks to "EmbeddedComposer".

[moufmouf]

EmbeddedComposer has been discontinued, but the overall idea remains sound.

TODO for Mouf 3: find a way to load dependencies in admin when dependencies in application are applied.

Note: we can find those with thecodingmachine/discovery.