Create documentation for how to use Invoke-ScubaCached

[buidav]

💡 Summary

Invoke-ScubaCached is a secret dev function we've been using since the beginning of SCuBA.

It was used as a way to speed up Rego development by running ScubaGear on a JSON that ScubaGear had already output.
ScubaCached bypassed reaching out to the tenant again and just runs the Rego rules and output the report.
The function was simplistic at first which meant telling people off hand to use it.

Now it's also being used as part of the functional test orchestrator and being used to test rego on injected settings that can't be tested on a live tenant. Along with additional parameters to support it's new capabilities

This issue is to officially document it's capabilities somewhere as it is grown more complex with additional features as time has gone on.

Motivation and context

Documentation a useful dev function that everyone should be using if they touch Rego.

Implementation notes

Somewhere in our documentation add a section for
How to use Invoke-ScubaCached

Acceptance criteria

Documentation for detailing how Invoke-ScubaCached is used and why it's used.