Allow customizing formatters on a per-field basis

[multimeric]

Is your feature request related to a problem? Please describe. I have several fields that I present to the user, but all of them result in very differently structured API requests. Therefore, I would like to be able to specify a JSON format for each of them, without having to create a custom operator each time.

Describe the solution you'd like Let's say we add the full range of format operations to the ValueField type, including sqlFormatOp, jsonLogic etc etc.