[Docs] README.md - content, separators, thumbnail, ToC, styling

## [Docs] README.md - content, separators, thumbnail, ToC, styling

<sub><b>the current PR does basically aim at:</b></sub>
- <sub><i>improving content</i></sub>
- <sub><i>separators</i></sub>
- <sub><i>thumbnail</i></sub>
- <sub><i>ToC</i></sub>
- <sub><i>styling</i></sub>

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<sub><b>let's make the web better bit by bit!!!</b></sub>

<img src="https://orig00.deviantart.net/5b95/f/2016/070/3/b/mit_license_logo_by_excaliburzero-d9ur2lg.png" width="70"></img> <img src="https://pbs.twimg.com/profile_images/821735271049768960/jJZXlJwZ.jpg" width="50"></img> <img src="https://i.vimeocdn.com/portrait/8650129_300x300" width="50"></img> <img src="https://media.licdn.com/mpr/mpr/shrinknp_200_200/AAEAAQAAAAAAAAzgAAAAJDM5ZWE5N2JkLTdiOWQtNDA5OC04Y2U1LTMwN2ZiZDg3NTg0ZA.jpg" width="50"></img>