get-started-experiments: delete all remote experiments in the push script

[iesahin]

The current push script built by generate.bash deletes the remote tags before pushing new tags to prevent older tags lurking around. It doesn't do this for the experiments and all older experiments remain in the repository after a new get-started-experiments repository is created.

We should delete all the experiments in the remote before this line in the push script:

dvc exp list --all --names-only | xargs -n 1 dvc exp push origin