Add .bazelrc file in project root, see

meisterT · meisterT · commit ff1092df4adc · 2018-11-14T08:08:12.000+01:00
bazelbuild/bazel#6319.
diff --git a/.bazelrc b/.bazelrc
@@ -0,0 +1 @@
+import %workspace%/tools/bazel.rc
