iOS app size

[Alystrasz]

CI-generated Pandemia.app file is 500MB+ big, which is too much to import it onto phones.

[rouvoy]

We should probably consider adding the --split-debug-info option to the build (https://flutter.dev/docs/perf/app-size#reducing-app-size)

[Alystrasz]

Instead of .app files, the AppStore requires .ipa files, maybe this file format is lighter.