oss/release: readme update (#744)

## Summary

## Cheour clientslist
- [ ] Added Unit Tests
- [x] Covered by existing CI
- [ ] Integration tested
- [ ] Documentation update



<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit

- **Documentation**
- Updated the README with a concise overview and disclaimer about this
repository being a fork of Airbnb’s Chronon.
- Highlighted key differences including additional connectors, upgraded
libraries, performance improvements, and specialized runners.
  - Clarified deployment options and maintenance practices.
- Removed detailed usage instructions, examples, and conceptual
explanations.
- Noted that full documentation is forthcoming and invited users to
contact maintainers for early access.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

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Co-authored-by: ezvz <[email protected]>

Author: nikhil-zlai