Bot command to retry failed CI jobs

[bkchr]

Sometimes CI jobs are failing and should be restarted. Normal users can not do this. So, we should add some bot command to do this.

[bkontur]

Please, please, please... This could be very useful.
In the past days/weeks, I have had several failed jobs that require a restart. For example, the Zombienet smoke test, which probably couldn't download the Docker image for some reason:

thread 'smoke' panicked at integration-tests/zombienet/tests/smoke.rs:15:42:
called `Result::unwrap()` on an `Err` value: ProviderError(NodeAvailableArgsError("docker.io/parity/polkadot:latest", "polkadot", ""))

https://github.com/polkadot-fellows/runtimes/actions/runs/12667467512/job/35302935630?pr=519