developer tool: list-apps.py to parse GarminDevice.xml

I added list-apps.py: https://github.com/flocsy/garmin-dev-tools/blob/main/scripts/list-apps.py to help developers parse GarminDevice.xml and extract the FileName for the logs.

list-apps.py [options] <GarminDevice.xml>
options:
    -h|--help
    -a|--app-id <app-id>            <app-id>: the id of the app in the manifest.xml
    -m|--manifest <manifest.xml>    <manifest.xml>: path to manifest.xml
    -f|--format <format>            <format>: can be either a comma separated list of tags
                                    or a lower case string of the characters "asfnvt" corresponding to the tags
                                    default: AppId,StoreId,FileName,AppName,Version,AppType

examples:

    to list all the tags of all the apps on the device:
        list-apps.py GarminDevice.xml

    to list all the tags of the app with app-id:
        list-apps.py -a 12345678-90ab-cdef-1234-567890abcdef ../../GARMIN/GarminDevice.xml

    to list the FileName of the app corresponding to the manifest:
        list-apps.py -m manifest.xml -f FileName GarminDevice.xml

    to list the AppName and Version:
        list-apps.py -fnv GarminDevice.xml