Add firmware for the Libra Mini (#270)

* Initial support, no joystick functionality

* remove vscode settings file

* Add non-vial default keymap

* Implement joystick mouse control for default and vial keymaps

* Add backslash to default keymap

* Add separate layout for stick-as-keys

* Remove references to unused layout

* Remove reference to unused custom matrix impl

keyboards/libra_mini/keymaps/default/config.h

@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+/* Mouse control configuration */
+
+/* Cursor speed */
+#define ANALOG_JOYSTICK_SPEED_MAX 5
+#define ANALOG_JOYSTICK_SPEED_REGULATOR 10
+
+/* Mouse inertia (keeps sliding after a flick) */
+// #define POINTING_DEVICE_GESTURES_CURSOR_GLIDE_ENABLE