NixOS/amazonImageZfs: init

Introduce an AWS EC2 AMI which supports aarch64 and x86_64 with a ZFS
root.

This uses `make-zfs-image` which implies two EBS volumes are needed
inside EC2, one for boot, one for root. It should not matter which
is identified `xvda` and which is `xvdb`, though I have always
uploaded `boot` as `xvda`.

(cherry picked from commit bd38b059eae05871579b2dfd51cd41d058b6a1ec)

nixos/release.nix

@@ -217,6 +217,20 @@ in rec {
     }).config.system.build.amazonImage)
 
   );
+  amazonImageZfs = forMatchingSystems [ "x86_64-linux" "aarch64-linux" ] (system:
+
+    with import ./.. { inherit system; };
+
+    hydraJob ((import lib/eval-config.nix {
+      inherit system;
+      modules =
+        [ configuration
+          versionModule
+          ./maintainers/scripts/ec2/amazon-image-zfs.nix
+        ];
+    }).config.system.build.amazonImage)
+
+  );
 
 
   # Test job for https://github.com/NixOS/nixpkgs/issues/121354 to test