DOCS: describe how component de-duplication works

[jkowalleck]

target: a new file "component_deduplication" in https://github.com/CycloneDX/cyclonedx-node-npm/tree/main/docs

related docs:

• https://github.com/CycloneDX/cyclonedx-node-npm/blob/main/docs/component_deduplication.md

goal:

• describe the need and reasoning
• have (alternative) processes described, how de-duplication could be achieved. which properties make components identical? {group,name,version,download-location,hashes,...}?
• have a clear decision which process is to be used

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💁 want to discuss? please use #307
-> there we have threats, votes, and everything we need