Change default file name for Rego output

[adhilto]

💡 Summary

Change the default value for OutRegoFileName from TestResults to RegoOutput.

Motivation and context

• With the current default value, it isn't clear to users what the purpose of the file is
• The TestResults.json file often gets confused with the ScubaResults.json file

Implementation notes

It's possible that some users rely on this file being named TestResults.json. However:

• Those users can always change the file name back to the old default by specifying -OutRegoFileName TestResults on the commandline or via a config file
• Any users using the TestResults.json file probably shouldn't, as the ScubaResults.json is more feature-rich and undergoes an additional round of validation that isn't reflected in the raw Rego output.

Acceptance criteria

• [ ] Change the default value of OutRegoFileName

[schrolla]

Requires updates to functional tests as well that hardcodes TestResults.json in a few places to allow tests to run properly.