feat(iota-data-ingestion-core): add README.md (#4570)

* feat(iota-data-ingestion-core): add README.md

* fixup! feat(iota-data-ingestion-core): add README.md

* Update crates/iota-data-ingestion-core/README.md

Co-authored-by: Konstantinos Demartinos <[email protected]>

* Update crates/iota-data-ingestion-core/README.md

Co-authored-by: Konstantinos Demartinos <[email protected]>

* fixup! fixup! feat(iota-data-ingestion-core): add README.md

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Co-authored-by: Konstantinos Demartinos <[email protected]>