Dashboard / CMS for mobile App

How to add extra web version with only the dashboard for admins, where they can manage content for the mobile app.

Is it possible with a single Meteor app? So I can crate 2 builds?

1: https://atmospherejs.com/yogiben/admin
2: http://orionjs.org/

Option 1 seems to be the most straightforward. Just follow the steps and you should have an admin backend ready from within the same project.
Option 2 is much more elaborate but has lot of customisation options.

The only issue you might have is the UI styles since both packages require Bootstrap… which may conflict with your Cordova specific CSS.

I dont want, that the dashboard code is build/packaged in to the app?

You should use two different meteor instances that share the same mongo db.

Josh Owens wrote an article about this http://joshowens.me/building-an-admin-app-as-a-microservice-with-meteor-js/.

I personnaly made a custom admin app and it works very well.