distrodefs: add aliases for ami and qcow2 bootc image types

cockpit-image-builder needs these aliases to map user-facing names
to the underlying image types. Translating at the frontend layer is
the wrong place for this — the definitions belong in the distrodefs.

Author: kingsleyzissou

data/distrodefs/bootc-generic/imagetypes.yaml

@@ -125,10 +125,12 @@ image_types:
 
   "ami":
     <<: *raw_image_type
+    aliases: ["aws"]
     filename: "disk.raw"
 
   "qcow2": &qcow2_image_type
     <<: *raw_image_type
+    aliases: ["guest-image"]
     filename: "disk.qcow2"
     mime_type: "application/x-qemu-disk"
     exports: ["qcow2"]