Support for primitive types in binary serialization union arrays

[jespertheend]

At the moment, only objects are supported in union arrays. However, we could possibly support primitive types as long as the types in the array are sufficiently different. For instance StorageType.STRING and StorageType.INT32.

[jespertheend]

Also doing something like

optionalType: [StorageType.UNION_ARRAY, StorageType.NULL, {myData: StorageType.STRING}

could be useful