Work on porting kittens to use new key infrastructure

Also move type definitions into their own module

kitty/main.py

@@ -17,7 +17,7 @@ from .cli_stub import CLIOptions
 from .conf.utils import BadLine
 from .config import cached_values_for
 from .constants import (
-    SingleKey, appname, beam_cursor_data_file, config_dir, glfw_path, is_macos,
+    appname, beam_cursor_data_file, config_dir, glfw_path, is_macos,
     is_wayland, kitty_exe, logo_data_file, running_in_kitty
 )
 from .fast_data_types import (
@@ -30,6 +30,7 @@ from .fonts.render import set_font_family
 from .options_stub import Options as OptionsStub
 from .os_window_size import initial_window_size_func
 from .session import get_os_window_sizing_data
+from .types import SingleKey
 from .utils import (
     detach, expandvars, find_exe, log_error, read_shell_environment,
     single_instance, startup_notification_handler, unix_socket_paths