Add initial IPFS Cluster support

It uses an encrypted data bag to store the cluster secret that has to be
the same on all members of a cluster. It installs ipfs-cluster-service
and ipfs-cluster-ctl and starts the cluster

Refs #25

data_bags/credentials/ipfs_cluster.json

@@ -0,0 +1,10 @@
+{
+  "id": "ipfs_cluster",
+  "secret": {
+    "encrypted_data": "oyy8QVRPvMx4YpHVqHr0WxX0D4WQMwZ43A1N+ZFa2jBlB/tzwzIz2gQv05L2\nf/2q4t4yXk6zTJRqPJ9kzcBddJCfuQPr8IzwdOZRz1UdXfE/iYY=\n",
+    "iv": "8+l2J0qmn6cKmGdf\n",
+    "auth_tag": "mgzeYpKJk6PSXjdcOP4CEg==\n",
+    "version": 3,
+    "cipher": "aes-256-gcm"
+  }
+}