My implementation of RPS / RPSLS

possible refactorings

• put XAML styles into Resources or ResourceDictionaries
• reading strings from a config file
• a general function for reading from a JSON file, insted of having two functions that do the same
• subclass Player for different player types and more granularity
• showing a dialog or other UI notification if an exception got catched
• async file reading handling
• if-else cleanup (i.e. one liner) but it's easier to reading
• adaptive ui
• always present current score on ui, not after the match
• more unit tests
• ...