Give a try to the new Kotlin Realm SDK

The Realm Kotlin SDK has been released as a stable version:

More details about the advantage of the new SDK can be found here: https://www.mongodb.com/docs/realm/sdk/kotlin/migrate-from-java-sdk-to-kotlin-sdk/

What we will have to check on our side:
- [x] Can the new SDK use DBs created with the Java SDK?
- [ ] How much time will it take to do the full migration? (having in mind so in a few months we may completely remove the dependency to Realm / but also we want to keep it to be able to handle the migration, so maybe for years)
- [x] Is the Realm SDK (and so the whole app) stable enough
- [x] It may also fix some not easy to fix bugs that we have since a long time like Realm instance not properly closed, or multi process trying to open the same Realm DB.

This impact #5842 and #3889

## Should you migrate now?

This is [recommended](https://www.mongodb.com/developer/products/realm/realm-java-to-kotlin-sdk/#should-you-migrate-now-) by the Realm team

### Links

- General documentation: https://www.mongodb.com/docs/realm/sdk/kotlin/
- Realm Kotlin beta SDK announcement: https://www.mongodb.com/docs/realm/sdk/kotlin/migrate-from-java-sdk-to-kotlin-sdk/
- Migration guide from the old SDK:
- doc: https://www.mongodb.com/docs/realm/sdk/kotlin/migrate-from-java-sdk-to-kotlin-sdk/
- tutorial : https://www.mongodb.com/developer/products/realm/realm-java-to-kotlin-sdk/