feat: add support for registing use force use invite code

web/src/views/admin/SysConfig.vue

@@ -27,6 +27,19 @@
         <el-form-item label="开放注册服务" prop="enabled_register">
           <el-switch v-model="system['enabled_register']"/>
         </el-form-item>
+        <el-form-item label="强制邀请码注册" prop="force_invite">
+          <el-switch v-model="system['force_invite']"/>
+          <el-tooltip
+              effect="dark"
+              content="开启之后，用户必须使用邀请码才能注册"
+              raw-content
+              placement="right"
+          >
+            <el-icon>
+              <InfoFilled/>
+            </el-icon>
+          </el-tooltip>
+        </el-form-item>
         <el-form-item label="短信服务" prop="enabled_msg">
           <el-switch v-model="system['enabled_msg']"/>
           <el-tooltip