Build devcontainer (Koenkk#2665)

* build(devcontainer): add devcontainer.json

* build(devcontainer): run `npm install` as `postCreateCommand`

Author: taasko

.devcontainer/devcontainer.json

@@ -0,0 +1,11 @@
+{
+  "image": "mcr.microsoft.com/devcontainers/javascript-node:18",
+
+  "postCreateCommand": "npm install",
+
+  "portsAttributes": {
+    "8080": {
+      "label": "client"
+    }
+  }
+}