chore: move zola infrastructure to deprecated/

Relocate legacy static site generator configuration to clear
namespace for new Rust-based compiler:

- config.toml, netlify.toml
- sass/, templates/ directories
- themes/apollo submodule (updated .gitmodules path)

Content directory preserved at root for compatibility.

deprecated/sass/fira.scss

@@ -0,0 +1,12 @@
+:root {
+    --text-font: 'Fira Sans', sans-serif;
+    --code-font: 'Fira Mono', monospace;
+}
+
+h1, h2, h3, h4, h5, h6 {
+    font-family: var(--code-font) !important;
+}
+
+header {
+    font-family: var(--code-font) !important;
+}