Changed generation of policySetDefinitions and improved whatif error handling

[daltondhcp]

Overview/Summary

Closing #418 and #396

This PR fixes/adds/changes/removes

1. Changed so policySetDefinitions generate parameter files instead of regular deployment templates to overcome escaping issues (Policy initiative with parameters will fail. #418)
2. Improved WhatIf/Validate error handling to throw terminating errors on template errors (Failure during validate marks task as succeeded (treat warnings as errors) #396)

As part of this Pull Request I have

• Checked for duplicate Pull Requests
• Associated it with relevant issues, for tracking and closure.
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Performed testing and provided evidence.
• Updated relevant and associated documentation.
• Updated the "What's New?" wiki page (located in the Enterprise-Scale repo in the directory: /docs/wiki/whats-new.md)

[daltondhcp]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[ljtill]

LGTM