[Data Driven Test Tool] Add YAML support

[stkillen]

Summary

Add support in the Data-driven Test Tool for uploading datasets in YAML file format.

YAML files are converted to JSON format and are as such a destructive action. Once uploaded and converted they are treated as JSON.

Multiple test cases are supported by defining a dictionary tests, e.g.:

tests:
- name: TEST01
  description: (...)
- name: TEST02
  description: (...)

(...)

A single test case can be uploaded with or without the tests key.

Work Item(s)

Fixes AB#555676