stages: Drop the remove-uniqueness stage

We don't need this stage anymore, random-seed has never been in
the tree and machine-id is now handled by dnf stage.

stages/org.osbuild.remove-uniqueness

@@ -1,16 +0,0 @@
-#!/usr/bin/python3
-
-import contextlib
-import json
-import os
-import sys
-
-def main(tree):
-    with contextlib.suppress(FileNotFoundError):
-        os.unlink(f"{tree}/etc/machine-id")
-        os.unlink(f"{tree}/var/lib/systemd/random-seed")
-
-if __name__ == '__main__':
-    args = json.load(sys.stdin)
-    r = main(args["options"])
-    sys.exit(r)