Add sitemap to wpcarro.dev

- Create ./website directory
- Add a sitemap to wpcarro.dev
- Move covid-uk directory to sandbox directory

TODO: Next sandbox, blog, and learn in the website directory

website/default.nix

@@ -0,0 +1,11 @@
+{ pkgs, ... }:
+
+pkgs.stdenv.mkDerivation {
+  name = "wpcarro.dev";
+  src = ./.;
+  buildPhase = ''
+    mkdir -p $out
+    cp $src/index.html $out
+  '';
+  dontInstall = true;
+}