/infra-config directory

Added /infra with chrome-infra specific files.
/infra/project-config/cr-buildbucket.cfg defines v8 buckets on cr-buildbucket.appspot.com

R=tandrii@chromium.org, machenbach@chromium.org, sergiyb@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1161143002

Cr-Commit-Position: refs/heads/master@{#28736}

infra/OWNERS

+machenbach@chromium.org
+sergiyb@chromium.org
+tandrii@chromium.org

infra/README.md

+This directory contains infra-specific files.

infra/project-config/README.md

+This directory contains v8 project-wide configurations for infra services.

infra/project-config/cr-buildbucket.cfg

+# Defines buckets on cr-buildbucket.appspot.com, used to schedule builds
+# on buildbot. In particular, CQ uses some of these buckets to schedule tryjobs.
+#
+# See http://luci-config.appspot.com/schemas/projects:buildbucket.cfg for
+# schema of this file and documentation.
+#
+# Please keep this list sorted by bucket name.
+
+buckets {
+  name: "master.tryserver.v8"
+  acls {
+    role: READER
+    group: "all"
+  }
+  acls {
+    role: SCHEDULER
+    group: "service-account-cq"
+  }
+  acls {
+    role: WRITER
+    group: "service-account-v8-master"
+  }
+}