Archive publicly-available testnet tx data

[iAmMichaelConnor]

We need to decide on sensible constants for all sorts of arrays of information that are emitted by the final tail private kernel circuit. This data will help infom such decisions.

Add a config option to testnet nodes to store all data of every tx they see. Perhaps we can exclude storing the "proof" (which is just incoherent maths), and only store the public inputs and underlying log data associated with a tx.