Refactor configuration file parsing

Now the time for importing the kitty.config module has been halved, from
16ms from 32ms on my machine. Also, the new architecture will eventually
allow for auto generating a bunch of python-to-C boilerplate code.

kitty/window.py

@@ -35,7 +35,7 @@ from .fast_data_types import (
 )
 from .keys import keyboard_mode_name
 from .notify import NotificationCommand, handle_notification_cmd
-from .options_stub import Options
+from .options.types import Options
 from .rgb import to_color
 from .terminfo import get_capabilities
 from .types import MouseEvent, ScreenGeometry, WindowGeometry
@@ -1016,8 +1016,8 @@ class Window:
         self.current_marker_spec = key
 
     def set_marker(self, spec: Union[str, Sequence[str]]) -> None:
-        from .options.utils import parse_marker_spec, toggle_marker
         from .marks import marker_from_spec
+        from .options.utils import parse_marker_spec, toggle_marker
         if isinstance(spec, str):
             func, (ftype, spec_, flags) = toggle_marker('toggle_marker', spec)
         else: