[Feature]: Visual Studio Code Language Server Integration

[Grant-Archibald-MS]

Is your feature request related to a problem? Please describe.

When editing a Test Engine yaml file with embedded Power Fx the Syntax Highlighting and Auto Complete IntelliSense should provide context to the author so that they are aware of the available variables and functions to author the test cases.

Describe the solution you'd like

Provide a Visual Studio Code language extension that provides the following:

• Knowledge of structure of a Power Apps Test Engine Yaml file format
• Embedding support for Power Fx included in the Yaml
• Support for out of the box Power Fx functions (For example CountRows())
• Support for additional TestEngine specific functions that may have been loaded
• Ability to interact with Symbols loaded into the Power Fx RecalcEngine for Canvas Apps, Custom Pages and Model Driven Applications

Describe alternatives you've considered

Consider the following existing components that could be reused, adapted or as needed

• YAML Language Support by Red Hat
• Microsoft.PowerFx.LanguageServerProtocol

Additional context?

Consider strategy that allows for single language (Power Fx) and multi language (Yaml + Power Fx) to incrementally improve the authoring experience