Added Zephyr settings and basic device in subsys. (#697)

* Added Zephyr settings subsys to enable storing of BACnet values according to BACnet object property value path.

* Added BACnet Basic features to enable basic samples. Refactored the zephyr BACnet profile B-SS sample to use BACnet basic subsys.

zephyr/subsys/bacnet_basic/bacnet_shell_packets.c

@@ -0,0 +1,38 @@
+/**
+ * @file
+ * @brief The BACnet shell commands for debugging and testing
+ * @author Steve Karg <skarg@users.sourceforge.net>
+ * @date May 2024
+ * @copyright SPDX-License-Identifier: MIT
+ */
+#include <stdlib.h>
+#include <stdint.h>
+#include <errno.h>
+#include <zephyr/shell/shell.h>
+/* BACnet definitions */
+#include "bacnet/bacdef.h"
+#include "bacnet/bacdcode.h"
+#include "bacnet/bactext.h"
+#include "bacnet/bacapp.h"
+/* Basic BACnet */
+#include "bacnet_basic/bacnet_basic.h"
+
+/**
+ * @brief Print BACnet packet statistics
+ * @param sh Shell
+ * @param argc Number of arguments
+ * @param argv Argument list
+ * @return 0 on success, negative on failure
+ */
+static int cmd_packets(const struct shell *sh, size_t argc, char **argv)
+{
+    (void)argc;
+    (void)argv;
+    shell_print(sh, "BACnet thread packets received: %ld",
+                bacnet_basic_packet_count());
+
+    return 0;
+}
+
+SHELL_SUBCMD_ADD((bacnet), packets, NULL,  "BACnet task packet stats", cmd_packets,
+		 1, 0);