added discord rpc (#1178)

* added discord rpc

* linting issues

* Revert "linting issues"

This reverts commit 55f4e39506.

* fix clang-format issues

* removed wrong rpc submodule

* added correct rpc submodule

* Moved cmake instructions to correct files.

* added minor suggestions from pr

* Added an option to enable/disable RPC, added rpc to emulator.cpp making it work on nonqt builds

* typo & minor stuff

* Changed getInstance implementation with Singleton class.

* Update discord_rpc_handler.cpp

discord id

* fixed ci clangformat errors

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Co-authored-by: georgemoralis <giorgosmrls@gmail.com>

src/common/config.h

@@ -18,6 +18,7 @@ bool isNeoMode();
 bool isFullscreenMode();
 bool getPlayBGM();
 int getBGMvolume();
+bool getEnableDiscordRPC();
 
 s16 getCursorState();
 int getCursorHideTimeout();
@@ -57,6 +58,7 @@ void setScreenHeight(u32 height);
 void setFullscreenMode(bool enable);
 void setPlayBGM(bool enable);
 void setBGMvolume(int volume);
+void setEnableDiscordRPC(bool enable);
 void setCursorState(s16 cursorState);
 void setCursorHideTimeout(int newcursorHideTimeout);
 void setLanguage(u32 language);