sway: Simplify input configuration

Simplify the input configuration in sway by setting the keyboard layout
based on the type and move the declaration from the device-specific
files to the main configuration file

sway/config

@@ -150,6 +150,12 @@ bindcode $mod+Shift+55 mode "$mode_system"
 # Systemd environment
 exec "systemctl --user import-environment; systemctl --user start sway-session.target"
 
+# Input configuration
+input type:keyboard {
+    xkb_layout de
+    xkb_variant neo
+}
+
 # Device specific configuration
 include device