settings: File selector & other settings

First of all, TASing requires a script to play back. The user can select the parent directory at `System -> Filesystem`, next to an option to pause TAS during loads: This requires a "hacky" setup deeper in the code and will be added in the last commit.

Also, Hotkeys are being introduced: CTRL+F5 for playback start/stop, CTRL+F6 for re-reading the script and CTRL+F7 for recording a new script.

src/common/settings.h

@@ -550,6 +550,9 @@ struct Values {
     BasicSetting<bool> gamecard_current_game{false, "gamecard_current_game"};
     BasicSetting<std::string> gamecard_path{std::string(), "gamecard_path"};
 
+    // TAS
+    bool pauseTasOnLoad;
+
     // Debugging
     bool record_frame_times;
     BasicSetting<bool> use_gdbstub{false, "use_gdbstub"};