改变目录结构，以防止ide混合打开前端项目，导致误操作改变前端项目的格式

Signed-off-by: trumansdo <1012243881@qq.com>

admin-core/pom.xml → plus-admin/admin-core/pom.xml

@@ -70,10 +70,6 @@
             <groupId>com.zaxxer</groupId>
             <artifactId>HikariCP</artifactId>
         </dependency>
-        <!--<dependency>
-            <groupId>mysql</groupId>
-            <artifactId>mysql-connector-java</artifactId>
-        </dependency>-->
         <!-- <dependency>
             <groupId>com.oracle</groupId>
             <artifactId>ojdbc6</artifactId>