[Cosmos] Support arbitrary T in query_databases and query_containers

[analogrelay]

The Cosmos query_databases and query_containers APIs currently return a Pager<DatabaseProperties> and Pager<ContainerProperties>. However, if a user projects different properties in their query, such as SELECT c.id as database_name FROM c, default deserialization fails. We should consider supporting arbitrary T values here, like the C# SDK does.

It's worth noting that today a user can still use deserialize_body_into to deserialize the body into a different type, so we could decide this scenario is already covered by that API.