Migrate to a Federated Plugin

**Is your feature request related to a problem? Please describe.**
Currently the plugin always has all dependencies, but chooses on runtime which maps plugin it will use. This means that we still have the Google Maps dependency in iOS.

**Describe the solution you'd like**
If we create a federated plugin, for example like geolocator or in_app_purchase we can only include those dependencies that are relevant for the platform and we could also allow others to create other platform versions, for example for flutter_map or huawei maps.

**Describe alternatives you've considered**

**Additional context**
https://docs.flutter.dev/packages-and-plugins/developing-packages#plugin