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/gitea.nix

@@ -24,6 +24,7 @@ in
         DOMAIN = "git.alicehuston.xyz";
         ROOT_URL = "https://git.alicehuston.xyz/";
         HTTP_PORT = 6443;
+        SSH_PORT = 2222;
       };
       service = {
         DISABLE_REGISTRATION = true;