Feat: add Eleventy to build documentation website

[MKlblangenois]

What is the change?

Add Eleventy to build automatically documentation website trough system like Netlify

Related issue?

closes: #26

Checklist:

• [x] I have followed the Code of Conduct.
• [x] I have checked there aren't other open Pull Requests for the same update/change.
• [x] I have you tested the code before submission.
• [x] I have commented my code, particularly in hard-to-understand areas.
• [x] My changes generates no new warnings.
• [x] I'm Hacktoberfest'21 contributor.

Screenshots