reorganization of _examples and add some new examples such as iris+groupcache+mysql+docker

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/request-body/read-query/main.go

@@ -0,0 +1,29 @@
+// package main contains an example on how to use the ReadForm, but with the same way you can do the ReadJSON & ReadJSON
+package main
+
+import (
+	"github.com/kataras/iris/v12"
+)
+
+type MyType struct {
+	Name string `url:"name"`
+	Age  int    `url:"age"`
+}
+
+func main() {
+	app := iris.New()
+
+	app.Get("/", func(ctx iris.Context) {
+		var t MyType
+		err := ctx.ReadQuery(&t)
+		if err != nil && !iris.IsErrPath(err) {
+			ctx.StopWithError(iris.StatusInternalServerError, err)
+			return
+		}
+
+		ctx.Writef("MyType: %#v", t)
+	})
+
+	// http://localhost:8080?name=iris&age=3
+	app.Listen(":8080")
+}