Use vfsgen instead of go-bindata (#7080)

* use vfsgen instead of go-bindata

* fix templates

* fix fmt

* vendor vsfgen

modules/templates/main.go

@@ -0,0 +1,23 @@
+// +build ignore
+
+package main
+
+import (
+	"log"
+	"net/http"
+
+	"github.com/shurcooL/vfsgen"
+)
+
+func main() {
+	var fsTemplates http.FileSystem = http.Dir("../../templates")
+	err := vfsgen.Generate(fsTemplates, vfsgen.Options{
+		PackageName:  "templates",
+		BuildTags:    "bindata",
+		VariableName: "Assets",
+		Filename:     "bindata.go",
+	})
+	if err != nil {
+		log.Fatal("%v", err)
+	}
+}