Add the go and nodejs modules, which own the toolchain packages and provide go-toolchain and node-toolchain (issue 1573)

modules/nodejs/README.md

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+# nodejs
+
+Node.js and npm as a module (novox/hq ADR 0477 §4, issue 1573).
+
+- **Owns the packages `nodejs` and `npm`.** No other module declares them (`checks/toolchains` refuses one that
+  does).
+- **Provides `node-toolchain` with the machine's reach**: dev-tools, lab and mesh-build-node require it, and the
+  requirement is met only by this module on the same machine. It is never pulled in for whatever asked, so
+  `nodejs` is assigned to a node on purpose, and a node without it refuses a module that needs it at resolution.
+- Holds no long-running resource, so it adds nothing to `health-undeclared`.
+
+The node-engine never uninstalls a package, so moving the declaration here removes nothing from a node.

modules/nodejs/module.json

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+{
+  "module": "nodejs",
+  "version": "1",
+  "capabilities": [
+    "package-manager"
+  ],
+  "provides": [
+    {
+      "name": "node-toolchain",
+      "reach": "machine"
+    }
+  ],
+  "resources": [
+    {
+      "id": "nodejs",
+      "type": "package",
+      "package": "nodejs"
+    },
+    {
+      "id": "npm",
+      "type": "package",
+      "package": "npm"
+    }
+  ]
+}