feat: add dev nix container

Author: npv2k1

templates/nix/.devcontainer/devcontainer.json

@@ -0,0 +1,20 @@
+
+{
+  "name": "nix",
+  "image": "mcr.microsoft.com/devcontainers/base:jammy",
+  "features": {
+    "ghcr.io/devcontainers/features/nix:1":{}
+  },
+
+  // Use 'forwardPorts' to make a list of ports inside the container available locally.
+  // "forwardPorts": [],
+
+  // Use 'postCreateCommand' to run commands after the container is created.
+  // "postCreateCommand": "uname -a",
+
+  // Configure tool-specific properties.
+  // "customizations": {},
+
+  // Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+  "remoteUser": "root"
+}