Implemented Windows registry read/write (#225)

* Implemented Windows registry read/write

* Simplify registry API and handle path writes

* Linux SetWorkingDirectory

* Implement reading path and unicode string from windows registry

* Use string_view value names for registry

* Use RegGetValueW

* Paths adjustments

* /

* Update working directory update failure message

* Updated linux SetWorkingDirectory

* Update flatpak define

* Remove RootDirectoryPath and save registry at startup

* dont save registry on exit

* Slight formatting update

---------

Co-authored-by: Sajid <sajidur78@gmail.com>

UnleashedRecomp/app.cpp

@@ -8,6 +8,7 @@
 #include <ui/game_window.h>
 #include <user/config.h>
 #include <user/paths.h>
+#include <user/registry.h>
 
 void App::Restart(std::vector<std::string> restartArgs)
 {
@@ -33,6 +34,7 @@ PPC_FUNC(sub_824EB490)
     App::s_isInit = true;
     App::s_isMissingDLC = !Installer::checkAllDLC(GetGamePath());
     App::s_language = Config::Language;
+    Registry::Save();
 
     __imp__sub_824EB490(ctx, base);
 }