Support for layered deployment manifests

[liliankasem]

It would be great to see support for layered deployments.

As per this issue, the generator says that systemModules are missing when trying to generate a manifest using a layered deployment template.

Our current layered deployment structure is as follows and is working great in our CD pipeline, but is unusable with any tooling locally. As a result, we also have a catch all deployment.template.json file that we're using to deploy and test modules locally. If there is guidance on a better approach, it would be appreciated!