
Create (or Delete) a preference: PREFERENCE (-del)

List preference formation example:
{
    "category" : "Streams",                       -> user choice;
    "type": "List",                               -> fixed as List;
    "key": "videostreams",                        -> user choice, must not repeate other key inside 
                                                     same preferences.json file;
    "title": "Streams to transform",              -> user choice;
    "summary": "Select video to transform",       -> user choice;
    "defaultValue": "0",                          -> must be a value listed in 'entryValues';
    "entries": ["sent", "received"],              -> names to the possible values listed in 'entryValues',
                                                     must have the same size as 'entryValues';
    "entryValues": ["0", "1"],                    -> list of possible values this preference can take;
    "scope": "plugin"                             -> if a preference value may be changed while the
                                                     functionality is being used, this functionality name
                                                     must be listed in the scope.
}

A List preference must have a list of possible values to be used.
and a list of 'names' for these values. For example:
    If you have two values: '0' and '1', these values may not be understandable
    by the user.
    The names 'sent' and 'received' set at 'entries' will be shown in the UI and
    are more intuitive!