Move gitiles module from milo to common/api.

common/api/gitiles/doc.go

Index: common/api/gitiles/doc.go
diff --git a/common/api/gitiles/doc.go b/common/api/gitiles/doc.go
new file mode 100644
index 0000000000000000000000000000000000000000..cd82efdad595bdbe33e64498ccf012670c6b4cbf
--- /dev/null
+++ b/common/api/gitiles/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2017 The LUCI Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package gitiles allows querying git repositories hosted *.googlesource.com.
+package gitiles