chore: Significantly restructure folder layout

This moves the various projects from "type-based" folders (such as
"services" or "tools") into more appropriate semantic folders (such as
"nix", "ops" or "web").

Deprecated projects (nixcon-demo & gotest) which only existed for
testing/demonstration purposes have been removed.

(Note: *all* builds are broken with this commit)

ops/journaldriver/default.nix

@@ -0,0 +1,9 @@
+{ pkgs, ... }:
+
+pkgs.third_party.naersk.buildPackage {
+  src = ./.;
+
+  buildInputs = with pkgs.third_party; [
+    pkgconfig openssl systemd.dev    
+  ];
+}