How to support registering ACF blocks with block.json method?

Currently ACF uses "the old way" of `acf_register_block` for block registration. Some newer features (such as block field validation in ACF 6.3) seem to only be supported for JSON-registered blocks. So blocks registered with Codifier are somewhat missing out on some features, and probably increasingly so.

It should be investigated if Codifier could utilize JSON registering in the future.