Add the ability to use and store build cache artifacts

Signed-off-by: Derek Straka <derek@asterius.io>
(cherry picked from commit 0adcc6e0bc)

scripts/publish-build-cache.sh

@@ -0,0 +1,13 @@
+#!/bin/bash -e
+
+if [[ $# -lt 1 ]]; then
+    echo "No Yocto branch specified, defaulting to master"
+    echo "To change this pass a Yocto branch name as an argument to this script"
+fi
+branch=${1-master}
+
+rsync -avz -e "ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null" --progress build/downloads yocto-cache@build-cache.asterius.io:/srv/yocto-cache/
+
+rsync -avz -e "ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null" --progress build/sstate-cache yocto-cache@build-cache.asterius.io:/srv/yocto-cache/${branch}/
+
+exit 0