`Node.send` sends already serialized json data via pydantic .json()

Requires: !96 (merged)

This change allows us to fully rely on the way pydantic (and thus schemas) serializes all types.

Before this MR, we were getting a dict structure with all models and serializing it in the communication.py module using the encoder placed there.

[x] - (top commit) - A fix in schemas clive is required for this to work as currently datetime objects serialize incorrectly as described in c0b2a61b