feat: organize all services into separate stacks by dependency

cache-infrastructure/nixcache/nginx.conf

@@ -0,0 +1,32 @@
+proxy_cache_path /var/cache/nginx/nix levels=1:2 keys_zone=nix_cache:32m max_size=60g inactive=365d use_temp_path=off;
+
+map $status $cache_header {
+  200     "public";
+  302     "public";
+  default "no-cache";
+}
+
+server {
+  listen 80;
+  server_name nix.dogar.dev;
+
+  location / {
+    proxy_pass https://cache.nixos.org;
+    proxy_http_version 1.1;
+
+    proxy_set_header Host cache.nixos.org;
+    proxy_set_header X-Real-IP $remote_addr;
+    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+    proxy_set_header X-Forwarded-Proto $scheme;
+
+    proxy_ssl_server_name on;
+
+    proxy_cache nix_cache;
+    proxy_cache_valid 200 302 365d;
+    proxy_cache_valid any 1m;
+    proxy_cache_use_stale error timeout updating http_500 http_502 http_503 http_504;
+
+    add_header X-Cache-Status $upstream_cache_status always;
+    add_header Cache-Control $cache_header always;
+  }
+}