update: system update & refactor

# Breaking Changes
- sops location movod to "system/dev/<dev-name>/sops/sops-conf.nix"
- flake devices declaration changes
- whole flake update

system/dev/dn-server/services/docmost.nix

@@ -0,0 +1,12 @@
+{ config, ... }:
+{
+  imports = [
+    (import ../../../modules/docmost.nix {
+      fqdn = "docmost.net.dn";
+      extraConf = {
+        MAIL_DRIVER = "smtp";
+      };
+      envFile = config.sops.secrets."docmost".path;
+    })
+  ];
+}