staging: Add journal0 node

```
journal0_summary =
hostname: journal0
fqdn: journal0.internal.staging.swh.network
network: ip=192.168.128.10/24,gw=192.168.128.1 macaddr=1E:98:C2:66:BF:33
```

Related T1875

proxmox/terraform/staging.tf

@@ -244,3 +244,21 @@ module "vault" {
 output vault_summary {
     value = "${module.vault.summary}"
 }
+
+module "journal0" {
+    source      = "./modules/node"
+    config      = "${local.config}"
+
+    hostname    = "journal0"
+    description = "Journal services node"
+    cores       = "4"
+    memory      = "16384"
+    network = {
+        ip      = "192.168.128.10"
+        macaddr = "1E:98:C2:66:BF:33"
+    }
+}
+
+output journal0_summary {
+    value = "${module.journal0.summary}"
+}

[Phabricator Migration user]

Some references in the commit message have been migrated:

• T1875 is now infra/sysadm-environment#1875