build bootstrap cache into ci image

.ci/packer_cache.sh

@@ -1,3 +1,21 @@
 #!/usr/bin/env bash
 
+# run setup script that gives us node, yarn, and bootstraps the project
 source "src/dev/ci_setup/setup.sh";
+
+# run the build for both oss and default distributions to warm the babel and optimizer caches
+node scripts/build;
+
+# cache es snapshots
+node scripts/es snapshot --download-only;
+
+# archive cacheable directories
+mkdir -p "$HOME/.kibana/bootstrap_cache"
+tar -cf "$HOME/.kibana/bootstrap_cache/master.tar" \
+  node_modules \
+  packages/*/node_modules \
+  x-pack/node_modules \
+  x-pack/plugins/*/node_modules \
+  optimize \
+  data \
+  .es;