Updated readme.md

[LinhNguyenLe2109]

Changes

• Moved About section to a new section call "How to use Graaf". I believe this title suit that section more
• Add a new About section. When I first read the project I had no idea what this one was about. I had to search online for a definition
• Moved "Installation" Section above "How to use...". I think this fits with the flow of most project more.
• Updated all links in the "Algorithms section". Some of them are wrong urls, I updated them and added other links to improve user experince
• Add a contributors list. It would be nice to see a list of people working on the project. Let me know if you think it's unnecessary

New found issues:

• I find the the installation guide is not consistent, the one on README and the one on the doc are quite different. So what should I use? Should it be on the doc or the one on README? I believe we need clearer instruction.
• In "How to use Graaf section", should we have a clearer guide and let the user actually create and see the result of the project? It would be nice if the user can perform some simple algorithms with their newly created graph

Let me know if you need any change.

[github-actions]

Hi there! Thank you for creating your first pull-request on the Graaf library :)

[codecov]

Codecov Report

All modified lines are covered by tests ✅

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[LinhNguyenLe2109]

@bobluppes HI can you see if the changes I made sufficent?

[bobluppes]

I find the the installation guide is not consistent, the one on README and the one on the doc are quite different. So what should I use? Should it be on the doc or the one on README? I believe we need clearer instruction.
In "How to use Graaf section", should we have a clearer guide and let the user actually create and see the result of the project? It would be nice if the user can perform some simple algorithms with their newly created graph

• Good point on the installation guide, we should definitely update that 😅 I created Installation guide is inconsistent #125 for this
• Regarding the "How to use Graaf section", that is also a good idea. Maybe we can reuse one of the examples there?

[bobluppes]

Thanks for the contribution, LGTM 🚀