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

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/webassembly/client/hello_go114.go

@@ -0,0 +1,16 @@
+// +build js
+
+package main
+
+import (
+	"fmt"
+	"syscall/js"
+	"time"
+)
+
+func main() {
+	// GOARCH=wasm GOOS=js /home/$yourusername/go1.14/bin/go build -o hello.wasm hello_go114.go
+	js.Global().Get("console").Call("log", "Hello Webassembly!")
+	message := fmt.Sprintf("Hello, the current time is: %s", time.Now().String())
+	js.Global().Get("document").Call("getElementById", "hello").Set("innerText", message)
+}