doc: Add Whitepaper in Docs #21249

What?

Add Bitcoin Whitepaper in Docs

Why?

The link to Whitepaper is removed from readme.md and Whitepaper should be part of Docs in this repository. Scammers should not be able to decide what can be removed from Bitcoin Core project. I think enough people and organizations have shown support after removal of whitepaper from Bitcoin Core website. Not all Bitcoin Core contributors or users were okay with the removal of whitepaper from website however a link to whitepaper or whitepaper itself needs to exist in this project.

How?

I created a directory for whitepaper in doc which can also be used to add images if necessary. Whitepaper can also be written in a better way or improved because I am not the best with markdown.

Alternatives: https://github.com/bitcoin/bitcoin/pull/21210/commits/77772a1b809e443a6861ee49009ff8bc55cff9c3#r577978996

Bitcoin Knots still has a link to whitepaper available on https://bitcoin.org : https://github.com/bitcoinknots/bitcoin/blob/0.21.x-knots/README.md

Other things: Some people may not be okay with sharing links related to https://bitcoin.org because of controversial people involved in managing the website so whitepaper can be written in a markdown file and added to docs. I removed www.bitcoin.org written below Satoshi's email address but I am not sure about this change. Also Line 46 in guiconstants.h https://github.com/bitcoin/bitcoin/blob/828bb776d29cbdfad3937ba100c428e3244c652f/src/qt/guiconstants.h#L46 has this domain and most probably it will remain being the origin domain.

Concept NACK. While scammers certainly have no relevance, the copyright status of this file is still unclear. Bitcoin.org arguably inherited an implied license from Satoshi, but I have seen nothing concrete to clearly show Satoshi has licensed it for distribution elsewhere. Considering that the whitepaper is of little relevance to the released code (even in 2009) nor understanding it (modern terminology differs significantly), I don't see any reason to add it to this repo.

the copyright status of this file is still unclear. Bitcoin.org arguably inherited an implied license from Satoshi, but I have seen nothing concrete to clearly show Satoshi has licensed it for distribution elsewhere.

Thoughts on below links? @luke-jr

https://github.com/bitcoin-core/bitcoincore.org/pull/740#issuecomment-764489652

https://twitter.com/opencryptoorg/status/1357757123493384194

Considering that the whitepaper is of little relevance to the released code (even in 2009) nor understanding it (modern terminology differs significantly), I don't see any reason to add it to this repo.

Whitepaper is an important document, none of the new devs who start researching about Bitcoin in future need to find it elsewhere and it should remain a part of Bitcoin Core IMO @fanquake Why is the PR closed?