distro/rhel84: use New York as default timezone

RHEl 8.4 guest images need to have the default timezone of EST/EDT
unless the user specifies one in their blueprint. New York is a major
location for this timezone.

test/data/manifests/rhel_84-x86_64-ami-boot.json

@@ -3097,6 +3097,12 @@
             "language": "en_US"
           }
         },
+        {
+          "name": "org.osbuild.timezone",
+          "options": {
+            "zone": "America/New_York"
+          }
+        },
         {
           "name": "org.osbuild.selinux",
           "options": {
@@ -9216,6 +9222,6 @@
       "tuned.service",
       "unbound-anchor.timer"
     ],
-    "timezone": "UTC"
+    "timezone": "New_York"
   }
 }