Convert fabric apps to packaged by default

[jonthysell]

Summary

Set all fabric apps (the playground-composition, e2e-test-app-fabric, and the new cpp-app template to create a package via their vcxproj files.)

Motivation

Right now neither playground-composition nor the e2e-test-app-fabric have any packaging project. The result is:

• The app exe can be opened with a regular double-click
• Debugging the app project from F5 in VS works
• run-windows doesn't work because there's no package to deploy
• The app folder contains a full copy of every dependency (even large framework packages like WinAppSDK)

Meanwhile, the cpp-app template has a secondary wappproj packaging project. The result is:

• The app exe cannot be opened with a regular double-click
• Debugging the app project from F5 in VS doesn't work (you need to debug the packaging project instead)
• run-windows does work because there's no package to deploy 👍
• The app folder containsonly what the app needs 👍

Basic Example

No response

Open Questions

No response

[jonthysell]

If we still want to support "unpackaged" apps (as the e2e-test-app-fabric and playground-composition apps currently do) we want to make sure that's something in our control, not hacked into the app's project files. We don't want anyone to change their mind mid-development and end up publishing a store app with loose copies of all the framework dependencies.