多模块重构 4：system 模块的创建，以及将相关的代码先进行迁移

yudao-framework/yudao-spring-boot-starter-mybatis/src/main/java/cn/iocoder/yudao/framework/mybatis/config/YudaoMybatisAutoConfiguration.java

@@ -15,7 +15,8 @@ import org.springframework.context.annotation.Configuration;
  * @author 芋道源码
  */
 @Configuration
-@MapperScan(value = {"${yudao.info.base-package}", "${yudao.core-service.base-package}", "${yudao.info.member-package}"},
+@MapperScan(value = {"${yudao.info.base-package}", "${yudao.core-service.base-package}",
+        "${yudao.info.member-package}", "${yudao.info.system-package}"},
         annotationClass = Mapper.class,
         lazyInitialization = "${mybatis.lazy-initialization:false}") // Mapper 懒加载，目前仅用于单元测试
 public class YudaoMybatisAutoConfiguration {

yudao-framework/yudao-spring-boot-starter-mybatis/src/main/java/cn/iocoder/yudao/framework/mybatis/core/enums/SqlConstants.java

@@ -0,0 +1,11 @@
+package cn.iocoder.yudao.framework.mybatis.core.enums;
+
+/**
+ * SQL相关常量类
+ */
+public interface SqlConstants {
+
+
+    String LIMIT1 = "LIMIT 1";
+
+}