fix: mirror binaries

This patch adds `upload:*` targets to the project that will upload the
binaries and put them in the GitLab generic package registry.

This requires a `~/.netrc` with a `api` token setup for `gitlab.arm.com`.

To upload all binaries perform the following:

    for TARGET in $(bazelisk query 'upload:*'); do
        bazelisk run --ui_event_filters -INFO -- "${TARGET}"
    done

Things to do in the future:

- Create a `multirun` upload target that does the upload in parallel
- Add a manually triggered CI job that does the upload
  - This will need a deploy token with _only_ package registry access

For now, a manual upload has been done help with outages.