flake updates

- remove deleted nixpkgs-stable pin for sops-nix
- remove kernel pin in global modules (defaults to LTS now)
- migrate nerdfonts to new pkgs.nerd-fonts namespace
- disable calibre-server on palatine-hill (for now)
- add SSH_PORT to gitea

Signed-off-by: ahuston-0 <aliceghuston@gmail.com>

systems/palatine-hill/configuration.nix

@@ -67,7 +67,7 @@
     nfs.server.enable = true;
     openssh.ports = [ 666 ];
     smartd.enable = true;
-    calibre-server.enable = true;
+    calibre-server.enable = false;
 
   };