Rename "Projects" to "App Layouts"

[plante-msft]

This is a comprehensive issue for all the string updates we need in the current UX for changing name from Projects to App Layouts.

• Rename module name in PowerToys settings list to "App Layouts"
• Rename all instances of "Projects" to "App Layouts" in dedicated settings page and change description string to "Launch a set of applications to your desired layout with one click."
• Rename all instances of "Projects" title editor (and edit sub-menu) to "App Layouts"
• Rename "Projects demo app" to "App Layouts Editor"
• Rename "+ Create project" button to "+ Create layout"

@donlaci @SeraphimaZykova is it troublesome to rename the projects.json file as well? If it's easy, I think we should rename it to applayouts.json and I will update the docs accordingly for users that want to access the file.

[donlaci]

@plante-msft The json file can be renamed easily.