Consistent JSON Serialisation Across Packages - `superjson`

[teddyjfpender]

Use consistent JSON serialisation across all packages with superjson.

@palladxyz/mina-graphql currently uses json-bigint to do both customFetch and as defaultJsonSerialization. Using superjson instead of json-bigint and JSON would make better and consistent JSON serialisation across Pallad as a product.

This was first attempted in https://github.com/palladians/pallad/pull/121 but with little luck.