Use template example-app for CI

[oskarth]

Problem

We currently use the more "heavy" https://github.com/oskarth/mopro/tree/main/mopro-ios and https://github.com/oskarth/mopro/tree/main/mopro-android for CI.

It'd be good to instead use the example app for this https://github.com/oskarth/mopro/tree/main/templates/mopro-example-app

Suggested solution

• Change CI to use template example app
• Remove legacy mopro-ios and mopro-android folders
• Optionally: also use mopro-cli to create example app instead of using the template itself (later on this might be non-executable code)