add metadata/profiles bits

We need these to declare this a proper repo for portage to recognize.

We use the name "eclass-overlay" so people don't get confused by a plain
"eclass" dir.

BUG=chromium:205164
TEST=`./update_chroot && ./build_packages --board=stumpy` works

Change-Id: Ib9fc3ccb7e40405461ee40df371372fa009df3b1
Reviewed-on: https://chromium-review.googlesource.com/179970
Reviewed-by: Chris Masone <cmasone@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/metadata/layout.conf b/metadata/layout.conf
new file mode 100644
index 0000000..acbc471
--- /dev/null
+++ b/metadata/layout.conf
@@ -0,0 +1,4 @@
+profile-formats = portage-2
+thin-manifests = true
+use-manifests = true
+cache-format = md5-dict
diff --git a/profiles/repo_name b/profiles/repo_name
new file mode 100644
index 0000000..4910e97
--- /dev/null
+++ b/profiles/repo_name
@@ -0,0 +1 @@
+eclass-overlay