Use vfsgen instead of go-bindata (#7080)

* use vfsgen instead of go-bindata

* fix templates

* fix fmt

* vendor vsfgen

vendor/github.com/shurcooL/httpfs/vfsutil/file.go

@@ -0,0 +1,21 @@
+package vfsutil
+
+import (
+	"net/http"
+	"os"
+)
+
+// File implements http.FileSystem using the native file system restricted to a
+// specific file served at root.
+//
+// While the FileSystem.Open method takes '/'-separated paths, a File's string
+// value is a filename on the native file system, not a URL, so it is separated
+// by filepath.Separator, which isn't necessarily '/'.
+type File string
+
+func (f File) Open(name string) (http.File, error) {
+	if name != "/" {
+		return nil, &os.PathError{Op: "open", Path: name, Err: os.ErrNotExist}
+	}
+	return os.Open(string(f))
+}