Check json configuration for errors with typed schema

[mkurkov]

Overview

Would be nice to have something like TypedSchema approach for automating loading from json maps to GrowthBook structs.
So from one description we could:

• generate defstruct field list with defaults
• generate type
• generate from_json function that will check field types and constraints

Example:

defmodule GrowthBook.Feature do
  use GrowthBook.TypedSchema
  
  typed_schema [
    id: integer(required: true),
    rules: list(GrowthBook.Feature, default: [])
  ]
end