feat: 新增多个服务类及工具类，重构部分代码结构

重构服务类结构，将分散的服务统一整合到service包下
新增ProjectConstant常量类及多个实体服务类
添加SecurityUtils安全工具类和BeanCacher工具类
优化部分UI控件和转换器的实现

client/src/main/java/com/ecep/contract/service/EmployeeRoleService.java

@@ -1,10 +1,18 @@
 package com.ecep.contract.service;
 
+import java.util.List;
+
 import com.ecep.contract.model.EmployeeRole;
+import com.ecep.contract.model.Function;
 import com.ecep.contract.vm.EmployeeRoleViewModel;
 
 public class EmployeeRoleService implements ViewModelService<EmployeeRole, EmployeeRoleViewModel> {
 
+    public List<Function> getFunctionsByRoleId(int i) {
+        // TODO Auto-generated method stub
+        throw new UnsupportedOperationException("Unimplemented method 'getFunctionsByRoleId'");
+    }
+
    
 
 }