[CHIA-3158] Add dicts to streamable

[Quexington]

This PR adds support for dicts to the streamable protocol. I'm unaware why this was not part of the existing design, but it will make certain uses much easier going forward.

Probably worth noting that this serialization makes the design situation that the "order" of the dictionary items (like how they'll be returned from .keys() and the like) is treated as unimportant in the deserialized form and will be deterministically serialized regardless of how the initial dictionary was constructed. However, this may result in a mismatch between the pre-serialized and de-serialized objects in this respect, yet the opinion is that this is an unimportant difference that no user should be relying on in any case.