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/infra/kubernetes/nginx/nginx.yaml

@@ -0,0 +1,60 @@
+# Deploy an nginx instance which serves ... redirects.
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: nginx-conf
+data:
+  nginx.conf: {{ insertFile "nginx.conf" | toJson }}
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx
+  labels:
+    app: nginx
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      labels:
+        app: nginx
+        config: {{ insertFile "nginx.conf" | sha1sum }}
+    spec:
+      containers:
+        - name: tazblog
+          image: nixery.local/shell/third_party.nginx:{{ .version }}
+          command: ["/bin/bash", "-c"]
+          args:
+            - |
+              cd /run
+              echo 'nogroup:x:30000:nobody' >> /etc/group
+              echo 'nobody:x:30000:30000:nobody:/tmp:/bin/bash' >> /etc/passwd
+              exec nginx -c /etc/nginx/nginx.conf
+          volumeMounts:
+            - name: nginx-conf
+              mountPath: /etc/nginx
+            - name: nginx-rundir
+              mountPath: /run
+      volumes:
+        - name: nginx-conf
+          configMap:
+            name: nginx-conf
+        - name: nginx-rundir
+          emptyDir: {}
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: nginx
+spec:
+  type: NodePort
+  selector:
+    app: nginx
+  ports:
+    - protocol: TCP
+      port: 6756
+      targetPort: 80