Switch to a single job to build the npm package

The architecture specific jobs pull it in and then build releases.

Much faster!

ci/build/lib.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+source ./ci/lib.sh
+
+# RELEASE_PATH is the destination directory for the release from the root.
+# Defaults to release
+RELEASE_PATH="${RELEASE_PATH-release}"
+
+rsync() {
+  command rsync -a --del "$@"
+}