[Matrix-SDK] Proper Session CoroutineScope management

At the moment we have a CoroutineScope defined in CryptoModule which is injected in some classes outside of crypto, this is not really clean.

https://github.com/vector-im/element-android/blob/2b629f130fc5b96a6f382442049680d5cbd72bc4/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/CryptoModule.kt#L132-L137

We should instead define this CoroutineScope in SessionModule and let it be managed in DefaultSession.
If need more scopes we should create them accordingly and inherits context from this root CoroutineScope (as we want them to be closed when session is closed).