Initial working Clueboard California Macropad w/ proton-c fixes

* Basic Clueboard Californai Macropad shield definition.
* New "direct" KSCAN driver that supports non-matrix direct
  wiring for switches, needed for macropad that doesn't have
  a matrix at all.
* Some renames for existing KSCAN GPIO driver to make the implied
  "matrix" part explicit.

app/boards/shields/clueboard_california/keymap/keymap.overlay

@@ -0,0 +1,24 @@
+#include <dt-bindings/zmk/keys.h>
+#include <dt-bindings/zmk/matrix-transform.h>
+#include <keymap.h>
+
+/ {
+	chosen {
+		zmk,keymap = &keymap0;
+	};
+	
+	keymap0: keymap {
+		compatible = "zmk,keymap";
+		label ="Default Kyria Keymap";
+		layers = <&default>;
+	};
+
+	layers {
+		compatible = "zmk,layers";
+
+		default: layer_0 {
+			label = "DEFAULT";
+			keys = <KC_9 KC_8 KC_7 KC_6 KC_5 KC_4 KC_3 KC_2 KC_1 KC_0>;
+		};
+	};
+};