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

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/request-body/read-custom-via-unmarshaler/main_test.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/kataras/iris/v12/httptest"
+)
+
+func TestReadCustomViaUnmarshaler(t *testing.T) {
+	app := newApp()
+	e := httptest.New(t, app)
+
+	expectedResponse := `Received: main.config{Addr:"localhost:8080", ServerName:"Iris"}`
+
+	e.POST("/").WithText("addr: localhost:8080\nserverName: Iris").Expect().
+		Status(httptest.StatusOK).Body().Equal(expectedResponse)
+}