Add yapf

Add yapf and yapf.bat with a vpython spec, so it can be used anywhere, e.g.
bots.

Change-Id: I363c0251ed766b2bb15a8c0f03615bc9a3ecb37a
Reviewed-on: https://chromium-review.googlesource.com/1107170
Commit-Queue: Nodir Turakulov <nodir@chromium.org>
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>

yapf

@@ -0,0 +1,17 @@
+#!/usr/bin/env vpython
+
+# [VPYTHON:BEGIN]
+# wheel: <
+#   name: "infra/python/wheels/yapf-py2_py3"
+#   version: "version:0.22.0"
+# >
+# [VPYTHON:END]
+
+# -*- coding: utf-8 -*-
+import re
+import sys
+
+from yapf import run_main
+
+if __name__ == '__main__':
+    sys.exit(run_main())