Rename tools/signing/deploy-legacy to tools/signing/redeploy-update_responses-release

Since we don't have anymore a legacy channel, we can remove the script tools/signing/deploy-legacy.

Or we can keep it as a script to re-deploy updates responses for a published release, renaming it to tools/signing/redeploy-update_responses-release and removing the small parts that are referencing the legacy release.

/cc @ma1