Some static-analysis support

[SteveL-MSFT]

Summary of the new feature / enhancement

Instead of hitting a run-time error, it would be useful to have some static analysis be performed. I do wonder if it should be part of whatIf or separate since whatIf will already handle some of it:

• schema validation of properties
• dependsOn circular loops (although this is caught early on during execution)
• [reference()] w/o explicit dependsOn
• [resourceId()] that doesn't exist (think typo)
• invalid functions or function arguments

Proposed technical implementation details (optional)

No response

[michaeltlombardi]

A command for validating a configuration document (and reference manifest, honestly) would be deeply useful for users and authoring tools alike, I think.

Maybe something like:

# By path
dsc validate document --path ./myconfig.dsc.config.yaml
# From stdin, with detailed info as JSON objects
$myConfig | dsc validate document --detailed
# As above, but for manifests:
$myResource | dsc validate manifest

The JSON objects from the output could contain information that the eventual extension could use, but at the very least they would tell the author the context and message that failed validation.

Another useful eventual option would be to enable suggestions, like using newer versions of resources, or noticing you're supplying a credential without using secureString, etc.