feat(bluetooth): Initial nRF52 BSIM based test support.

Co-authored-by: Cem Aksoylar <caksoylar@users.noreply.github.com>

app/boards/native_posix_64.overlay

@@ -4,6 +4,7 @@
 
 / {
     chosen {
+        zephyr,console = &uart0;
         zmk,kscan = &kscan;
     };
 
@@ -15,4 +16,13 @@
         columns = <2>;
         exit-after;
     };
+
+    uart0: uart {
+        status = "okay";
+        compatible = "zephyr,native-posix-uart";
+        /* Dummy current-speed entry to comply with serial
+         * DTS binding
+         */
+        current-speed = <0>;
+    };
 };

app/boards/nrf52_bsim.conf

@@ -0,0 +1,4 @@
+CONFIG_ZMK_BLE=y
+CONFIG_LOG=y
+CONFIG_LOG_BACKEND_SHOW_COLOR=n
+CONFIG_ZMK_LOG_LEVEL_DBG=y

app/boards/nrf52_bsim.overlay

@@ -0,0 +1,17 @@
+#include <behaviors.dtsi>
+#include <dt-bindings/zmk/keys.h>
+#include <dt-bindings/zmk/kscan_mock.h>
+
+/ {
+    chosen {
+        zmk,kscan = &kscan;
+    };
+
+    kscan: kscan {
+        compatible = "zmk,kscan-mock";
+        label = "KSCAN_MOCK";
+
+        rows = <2>;
+        columns = <2>;
+    };
+};