Derives for high performance JSON serialisation (and eventually deserialisation).

Attributres are supported for both #[simd_json(...)] and for compatibilty also for #[serde(...)] and follow the same nameing conventions as serde.

For fields:

• rename = "new_name" - renames a field

For structs:

• rename_all = "camelCase" - renames all (not otherwise renamed) based on the rule, camelCase is currently supportd