Remove hardcoded streams

[nikita-lavrov]

Summary

Related to https://github.com/elastic/streams-program/issues/402

This PR removes all the hardcoded ingest pipelines, index and component templates from the streams challenges, since it is now possible to automatically preconfigure streams using Kibana.

[gbanasiak]

LGTM

[gareth-ellis]

Since this is a public repo, could you include details here of what would need setting up? External users won't have access to esbench

[nikita-lavrov]

Addressed in 9ec4c1b

[esbenchmachine]

@nikita-lavrov
A backport is pending for this PR.
Apply all the labels that correspond to Elasticsearch minor versions expected to work with this PR, but select only from the available ones.
If intended for future releases, apply label for next minor

When a vX.Y label is added, a new pull request will be automatically created, unless merge conflicts are detected or if the label supplied points to the next Elasticsearch minor version. If successful, a link to the newly opened backport PR will be provided in a comment.

In case of merge conflicts during backporting, create the backport PR manually following the steps from README:
Final steps to complete the backporting process:

1. Ensure the correct version labels exist in this PR.
2. Ensure each backport pull request is labeled with backport.
3. Review and merge each backport pull request into the appropriate version branch.
4. Remove backport pending label from this PR once all backport PRs are merged.

Thank you!