RFC: Remove experimental MapEffect composable

If you would like to recommend against this proposal, please comment below or react with 👎 .
-------------

MapEffect was added in #140 to expose the underlying GoogleMap Maps SDK object to enable extension and usages such as clustering with the utility library.

With Compose-native clustering being added by #258, we're hoping that MapEffect is no longer needed. Providing direct access to the map is potentially buggy as noted in [this comment](https://github.com/googlemaps/android-maps-compose/pull/140#pullrequestreview-1003063252).

It seems like MapEffect would still be necessary for other Android Maps Utils such as GeoJSON layer (#29) and KML layer (#129).

**Please comment below if you have other use cases that would require exposing the map object.**

Inizia esaminando l'introduzione di MapEffect in #140, il lavoro sul clustering nativo di Compose in #258 e i casi d'uso rimanenti di GeoJSON e KML in #29 e #129. Il lavoro sarà considerato completato quando sarà stato stabilito se questi casi d'uso necessitano ancora dell'accesso diretto alla mappa e la decisione risultante sarà stata documentata o implementata.

Scritto dal modello di indicizzazione a partire dal testo della issue.