move repos to toplevel json file

pungi can't substitute in any included files so we end up
with errors because 'fedora-rawhide' repo isn't accessible
during the pungi run.

Signed-off-by: Dusty Mabe <dusty@dustymabe.com>

fedora-common-ostree.json

@@ -1,6 +1,5 @@
 {
     "ref": "fedora/rawhide/${basearch}/ostree-base",
-    "repos": ["fedora-rawhide"],
 
     "automatic_version_prefix": "29",
     "mutate-os-release": "29",

silverblue.json

@@ -1,5 +1,6 @@
 {
     "ref": "fedora/rawhide/${basearch}/workstation",
+    "repos": ["fedora-rawhide"],
 
     "include": "gnome-desktop-pkgs.json",