Create .gitignore and update copyright info
Migrate udev keymaps to hwdb data file

From systemd 206 changelog:
The udev "keymap" data files and tools to apply keyboard
specific mappings of scan to key codes, and force-release
scan code lists have been entirely replaced by a udev
"keyboard" builtin and a hwdb data file.
Support swapping 'Alt' and 'Cmd' keys to emulate PC keyboard layout