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)

web/tazblog/static/blog.css

@@ -0,0 +1,35 @@
+body {
+    margin: 40px auto;
+    max-width: 650px;
+    line-height: 1.6;
+    font-size: 18px;
+    color: #383838;
+    padding: 0 10px
+}
+h1, h2, h3 {
+    line-height: 1.2
+}
+.footer {
+    text-align: right;
+}
+.lod {
+    text-align: center;
+}
+.unstyled-link {
+    color: inherit;
+    text-decoration: none;
+}
+.uncoloured-link {
+    color: inherit;
+}
+.date {
+    text-align: right;
+    font-style: italic;
+    float: right;
+}
+.inline {
+    display: inline;
+}
+.navigation {
+    text-align: center;
+}