Refactor and standardize all JSON validator errors with human readable

Summary

1. Currently all json validator errors spit out exceptions based on regex. Not all end users understand regex and would be much better suited with friendly error messages.
2. JSON error payloads are not consistent throughout the codebase. They need to all be consistent so developers and API users know what to expect regardless of what handler they are accessing
3. Implements discussion in !767 (merged)

Area of the system

All handlers

How does this currently work?

Currently payloads are not consistent and validators spit out nondescript exceptions

What is the desired way of working?

JSON error payloads should all be the same. Validators should fail descriptly.

Priority/Severity

• High (This will bring a huge increase in performance/productivity/usability)
• Medium (This will bring a good increase in performance/productivity/usability)
• Low (anything else e.g., trivial, minor improvements)