Revert "Remove clang-format template: this does not need to be bound to the rest of clang versioning"

This reverts commit df6891e2f3.

templates/tools/dockerfile/grpc_clang_format/Dockerfile.template

@@ -0,0 +1,23 @@
+%YAML 1.2
+--- |
+  # Copyright 2015 gRPC 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.
+  
+  FROM debian:jessie
+  
+  <%include file="../clang_format.include"/>
+  ADD clang_format_all_the_things.sh /
+  CMD ["echo 'Run with tools/distrib/clang_format_code.sh'"]
+  
+