docs: add attestation service documentation and diagram (#105)

## Summary by Sourcery

Documentation:
- Add comprehensive documentation for the Ethereum Attestation Service
(EAS), including an introduction, key concepts, workflow, contract
deployment, schema registration, attestation creation, verification
methods, and integration studio implementation.

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Co-authored-by: saeeddawod <saeed.dawod@gmail.com>
Co-authored-by: Roderik van der Veer <roderik@settlemint.com>
Co-authored-by: sourcery-ai[bot] <58596630+sourcery-ai[bot]@users.noreply.github.com>

Author: 4 people