Add NB-IoT BC28 model driver base connection framework base on AIIT_ARM board

it is fit

applications/connection_demo/nbiot_demo/Makefile

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+SRC_FILES :=nbiot_demo.c
+
+include $(KERNEL_ROOT)/compiler.mk

applications/connection_demo/nbiot_demo/nbiot_demo.c

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+/*
+* Copyright (c) 2020 AIIT XUOS Lab
+* XiUOS is licensed under Mulan PSL v2.
+* You can use this software according to the terms and conditions of the Mulan PSL v2.
+* You may obtain a copy of Mulan PSL v2 at:
+*        http://license.coscl.org.cn/MulanPSL2
+* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
+* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
+* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
+* See the Mulan PSL v2 for more details.
+*/
+
+/**
+ * @file nbiot_demo.c
+ * @brief Demo for NBIoT function
+ * @version 1.0
+ * @author AIIT XUOS Lab
+ * @date 2021.04.22
+ */
+
+#include <string.h>
+#include <user_api.h>
+#include <xs_adapter_at_agent.h>
+#include <xs_adapter_manager.h>
+#include <xs_adapter_at_nbiot.h>
+
+extern void RegisterAdapterNBIoT(void);
+
+void NbiotEnable(void)
+{
+    RegisterAdapterNBIoT();
+
+    struct AdapterAT* at_adapter =  ATAdapterFind(NBIOT_ADAPTER_ID);
+
+    UserTaskDelay(5000);
+    
+    at_adapter->parent.done.NetAiitOpen(&at_adapter->parent);
+
+    printf("Waiting for msg...\n");
+
+    at_adapter->atdone.ATSocketCreate(at_adapter, 1, SOCKET_TYPE_STREAM, NET_TYPE_AF_INET);
+    UserTaskDelay(1000);
+
+    struct AddressIpv4 addr;
+    addr.ipv4 = IpTint("115.236.53.226");
+    at_adapter->atdone.ATSocketConnect(at_adapter, 1, addr, 8989, 0);
+
+    int socket_fd = 1;
+    int count = 0;
+
+    while (1) {
+        UserTaskDelay(1000);
+        at_adapter->parent.done.NetAiitSend((struct Adapter *)at_adapter, "AB30313233", 5, 0, 0, 0, 0, 0, &socket_fd);
+        count++;
+        if (count == 10)
+            break;
+    }
+}