appiumtests: port touchinputsynth library to CPython extension

For a less flaky and faster test
- The event loop is not blocked when executing touch_move commands, so the MPRIS D-Bus interface in the Python side can still receive signals when testing touch gestures.
- `is_window_maximized` is run in the Python side instead of using BlockedQueuedConnection, so the event loop will not be blocked when maximizing a window.
- Calling CPython module functions is faster than calling functions generated by ctypes.CDLL