Implement changes needed in the Host to decouple workers from the Host release

[surgupta-msft]

Implement a resolver whose responsibility will be to find the Worker Configs based on multiple factors such as -

• Worker location
• Worker release chanel
• Fallback mechanism to the default flow
• Platform - windows and linux
• Finding the compatible worker
• Feature flag enablement
• Also, add tests for the resolver

Refer to the design doc of Decoupling workers for more details on each of these factors.