Adds a UI for accepting Discord join requests in Dolphin

also did these things
fixed crash from joining user that isn't hosting via a direct connection
current game stat can now pass to override the current game in config
uses ip endpoint from dolphin.org

Source/Core/DolphinQt/CMakeLists.txt

@@ -9,6 +9,7 @@ add_executable(dolphin-emu
   AboutDialog.cpp
   CheatsManager.cpp
   DiscordHandler.cpp
+  DiscordJoinRequestDialog.cpp
   FIFO/FIFOPlayerWindow.cpp
   FIFO/FIFOAnalyzer.cpp
   HotkeyScheduler.cpp