Updated Readme.md of Blockchain folder

[khushbooag4]

Have you read the Contributing Guidelines on Pull Requests?

eractCoding/NeoAlgo/blob/master/CONTRIBUTING.md#pull-requests)?

(Write your answer here.)

Description

I have added some description about blockchain and bitcoin cyptocurrency technology. They are highly demand and basic learning resources are missing in the web . So I have concise explanation to basic definations. Kindly review it

Checklist

• [x] I've read the contribution guidelines.
• [x] I've checked the issue list before deciding what to submit.
• [x] I've edited the README.md and link to my code.

Related Issues or Pull Requests

I have contributed my writings on the readme.md of blockchain folder. Kindly merge it

[khushbooag4]

Has it been merged

[github-actions[bot]]

Please reopen this pull request once you commit the changes requested or make improvements on the code. If this is not the case and you need some help, feel free to seek help from our Discord or ping one of the reviewers. Thank you for your contributions!