feat(new sink): Initial datadog_events sink (vectordotdev#7678)

* Initial

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* Fixes

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* Fixes

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* Tests

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* Add docs

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* Add semantic

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* Move url

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* Fix url

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* Add request docs

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* Add batch docs

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* Bump

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* Clippy

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* Apply feedback

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* Apply feedback

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* Add use

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* Bump

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