Package sandbox for easy SMART App Launch (app-in-iframe) development

[shanejearley]

Is your feature request related to a problem? Please describe.
FHIR kit needs to support the SMART App Launch use-case. This enables passing context from EHR launch events, which can even be triggered by CDS Hooks.

Describe the solution you'd like
SMART App Launch development client like (or with) the one here with docker and app development configuration or documentation. The app developer should be able to access this feature with a CLI and pair it with any frontend application with ease. Managing ngrok URLs for local development in the EHR environment with hot reloading is a requirement.

@hawyar this issue won't include auth yet, or at least if it does, it will be in very minimal, mocked capacity. We'll need to meet in the near future and scope that out, prioritizing an easy integration with Cognito for managing clinical users in AWS (and specifically integrating with HealthNet). Besides that, this package will simply serve an EHR client that embeds the app developer's frontend development server in the client's iframe (as it would be in a real-world EHR client) through a CLI interface with some handy defaults and automation.

Describe alternatives you've considered
None.

Additional context
None.