Duplicated application IDs when an example is copied from common to a platform directory

[martacarbone]

When an example application (such as blink) is copied from the examples/common directory into a specific platform directory (like platform_unoq), arduino-app-cli app list returns duplicate entries with identical IDs.

When invoking the API endpoint to start the application using its identifier, the internal engine use the platform version.
We need to apply the same concept to the all list, by allowing the platform specific version to win over the common one.

arduino@SuperVicky:/var/lib/arduino-app-cli/examples/common$ arduino-app-cli app list |grep examples:blink
examples:blink                               Blink LED                               🔴   uninitialized true    
examples:blink-with-ui                       Blink LED with UI                       💡   uninitialized true    
arduino@SuperVicky:/var/lib/arduino-app-cli/examples/common$ cp -r blink ../platform_unoq/
arduino@SuperVicky:/var/lib/arduino-app-cli/examples/common$ arduino-app-cli app list |grep examples:blink
examples:blink                               Blink LED                               🔴   stopped       true    
examples:blink                               Blink LED                               🔴   uninitialized true    
examples:blink-with-ui                       Blink LED with UI                       💡   uninitialized true    
arduino@SuperVicky:/var/lib/arduino-app-cli/examples/common$ 

[lucarin91]

The design of the features is that examples could either be in the common folder if they should be available for the board, or in one or multiple platform_ folders. If an example is present both in common and in one of the platform_ folders, this is an issue with the example's structure. I don't think we should explicitly check for this case; at most we could add a validation check during build.