serde support

[liamcurry]

Serde is the defacto standard when it comes to serializing and deserializing data. It will be necessary for table structs to support Serde's Serialize/Deserialize traits in order to implement the RPC API later on.

Implementing this will require writing custom serializers/deserializers for EOS types, for example:

• Booleans are 0 or 1
• Large numbers can sometimes be integers, sometimes be strings