feat(shields): Added Waterfowl shield

app/boards/shields/waterfowl/waterfowl_left.overlay

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2022 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "waterfowl.dtsi"
+
+&kscan0 {
+	col-gpios
+		= <&pro_micro 21 GPIO_ACTIVE_HIGH>
+		, <&pro_micro 20 GPIO_ACTIVE_HIGH>
+		, <&pro_micro 19 GPIO_ACTIVE_HIGH>
+		, <&pro_micro 18 GPIO_ACTIVE_HIGH>
+		, <&pro_micro 15 GPIO_ACTIVE_HIGH>
+		;
+};
+
+&left_encoder {
+	status = "okay";
+};