Adds support for app execution alias

[harvinders]

PR checklist

Quick summary of changes This PR adds support for invoking the app from the command line using the app execution alias by defining it in the appxmanifest file

Which issue does this PR relate to?

4695

Applies to the following platforms:

• [x] WinUI
• [ ] WPF
• [ ] UWP

Anything that requires particular review or attention? No

Do all automated tests pass? N/A

Have automated tests been added for new features? N/A

If you've changed the UI:

• Be sure you are including screenshots to show the changes.
• Be sure you have reviewed the accessibility checklist. N/A

If you've included a new template:

• Be sure you reviewed the Template Verification Checklist.
• Be sure it's included in the list on this UWP or WPF getting started doc. N/A

Have you raised issues for any needed follow-on work? N/A

Have docs been updated? N/A

If breaking changes or different ways of doing things have been introduced, have they been communicated widely? N/A

[Mysterious-Dev]

If it's a PR that can be merged, personally, I'd see it more as a template alongside the basic one (like self-contained) with mstest as a dependency or as a dependency of mstest

[mrlacey]

Yes, this feel like it should be a separate feature, and not always included (especially without adding to the documentation of this option)

I don't see the connection to the mstest option though? @Mysterious-Dev ?

[Mysterious-Dev]

It is currently not possible to invoke the application from command line. This removes one option to start the application for the user. It also makes it bit tricky to test the application if a tester wants to use the Process class to start the application. Test automation writers have to depend on shell to start the application.

@mrlacey I may have confused automated tests with mstest

[pratikone]

Yeah, it works best as an option like Self-Contained called maybe "launch from command line". however, you only need it for packaged apps (MSIX packaging option included). Unpackaged apps don't need it because you can directly launch the .exe. So the template option needs to be conscious about it.