Extract validation logic so it can be re-used in CI pipelines

[deanward81]

I've been making heavy use of this extension and it's fantastic, kudos to all those working on it! Whilst this is great for local development and validation of templates, we have a need to be able to perform a similar set of validations to those provided by the extension in our CI pipeline.

Currently we make use of the ARM Test Toolkit to perform rudimentary validation and linting of our ARM templates. Validation capabilities in the VS Code extension far exceed the capabilities of the toolkit (mostly, it seems, because the extension understands the full AST of the template) and it strikes me that being able to use the capabilities outside of VS Code would be extremely useful.

I'd love to see the schema and parameter validation features extracted from the VS Code extension so they could, for example, be consumed by a NodeJS tool that validates ARM templates in a CI pipeline.

Is this something the team has considered? Or is it already possible and I'm missing something obvious?