Provide a colourized and focused diff around ARM template JSON regressions

[ninjarobot]

The changes in this PR are as follows:

• Adds a colorized diff for JSON regressions based off Expecto.Diff. Intending to push some fixes to Expecto.Diff to improve it for large comparisons.

I have read the contributing guidelines and have completed the following:

• [ ] Tested my code end-to-end against a live Azure subscription.
• [ ] Updated the documentation in the docs folder for the affected changes.
• [ ] Written unit tests against the modified code that I have made.
• [ ] Updated the release notes with a new entry for this PR.
• [ ] Checked the coding standards outlined in the contributions guide and ensured my code adheres to them.

If I haven't completed any of the tasks above, I include the reasons why here:

This is an update to the JSON regression tests to improve the development workflow for contributors and does not make changes to the Farmer library itself.