Start work on applying JSON schemas

[extremeheat]

We will take in JSON schemas and use them to type the fields inside the DSV file. Additionally, we can extend the JSON schema by having "preprocess" instructions on transforming a string to structured data. For example, inside a CSV file, we may want one of the columns to have nested data such as an array of Unix dates, like such:

flight,destination,times
SQ11,Tokyo,1693700173;1693771027

{
  "preprocessTransforms": [
    { "splitBy": ";", "types": "number" }
  ]
}

would parse the 3rd column from a string concatenation of "1693700173;1693771027" as an array of numbers [1693700173, 1693771027] in JS. This could then be passed to json schema validator like AJV for schema validation.