Make necessary changes for 23.05

- Explicitly enable fish
- No longer use OpenSSL 1.1 for BURP (decryption now seems to work fine
  with current OpenSSL)
- Move sshd settings to `settings`

base/defaults.nix

@@ -6,8 +6,10 @@
         services.xserver.layout = "us-fruchti";
         services.openssh = {
             enable = true;
-            passwordAuthentication = false;
-            kbdInteractiveAuthentication = false;
+            settings = {
+                PasswordAuthentication = false;
+                KbdInteractiveAuthentication = false;
+            };
         };
 
         nix.gc = {