Migrate existing keycode-based keybindings (#16049)

Co-authored-by: grorp <gregor.parzefall@posteo.de>
Co-authored-by: sfan5 <sfan5@live.de>

src/settings.cpp

@@ -22,6 +22,7 @@
 Settings *g_settings = nullptr;
 static SettingsHierarchy g_hierarchy;
 std::string g_settings_path;
+bool g_first_run = false;
 
 std::unordered_map<std::string, const FlagDesc *> Settings::s_flags;