Tetris external app (#1842)

* Tetris external app
* 4 levels

firmware/application/external/tetris/ui_tetris.cpp

@@ -0,0 +1,39 @@
+#include "ui_tetris.hpp"
+
+namespace ui::external_app::tetris {
+
+#pragma GCC diagnostic push
+// external code, so ignore warnings
+#pragma GCC diagnostic ignored "-Weffc++"
+#include "tetris.cpp"
+#pragma GCC diagnostic pop
+
+TetrisView::TetrisView(NavigationView& nav)
+    : nav_(nav) {
+    add_children({&dummy});
+}
+
+void TetrisView::paint(Painter& painter) {
+    (void)painter;
+
+    if (!initialized) {
+        initialized = true;
+        std::srand(LPC_RTC->CTIME0);
+        main();
+    }
+}
+
+void TetrisView::frame_sync() {
+    check_fall_timer();
+    set_dirty();
+}
+
+bool TetrisView::on_encoder(const EncoderEvent delta) {
+    return check_encoder(delta);
+}
+
+bool TetrisView::on_key(const KeyEvent key) {
+    return check_key(key);
+}
+
+}  // namespace ui::external_app::tetris