Join project info

Starting the changes proposed in #396 

- [x] Move the content from `_posts/projects/*` to `_data/mvp.yml`
- [x] Ensure both `pt-BR` and `en` versions are working properlly
- [x] Update README.md with the new way to add projects

Now it's ready for merge. Please give a look in staging.helabs.com.br.

Closes #396