Reapply "feat(controller): 完善基础控制器及默认页面渲染"

This reverts commit 1a3bd1a6b3.

controller/admin/baseController.go

@@ -0,0 +1,13 @@
+package admin
+
+import "github.com/gin-gonic/gin"
+
+type BaseController struct {
+}
+
+func (con BaseController) Success(c *gin.Context) {
+	c.String(200, "成功")
+}
+func (con BaseController) Error(c *gin.Context) {
+	c.String(200, "失败")
+}