feat(ops/modules): set up public-inbox at inbox.tvl.su

Initial setup which does not yet include fetching mails at all, this
is for now only going to display a manually populated view of the
existing mailing list while the rest of this stuff is set up.

Change-Id: Ie1235bd257c9056fe37d0740dfca771ebdd880eb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7628
Reviewed-by: flokli <flokli@flokli.de>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI

ops/modules/www/inbox.tvl.su.nix

@@ -0,0 +1,24 @@
+{ config, ... }:
+
+{
+  imports = [
+    ./base.nix
+  ];
+
+  config = {
+    services.nginx.virtualHosts."inbox.tvl.su" = {
+      enableACME = true;
+      forceSSL = true;
+
+      extraConfig = ''
+        location = / {
+          return 302 https://inbox.tvl.su/depot;
+        }
+
+        location / {
+          proxy_pass http://localhost:${toString config.services.public-inbox.http.port};
+        }
+      '';
+    };
+  };
+}