Improve nav bar and switch locale menu

[espinosajuanma]

Right now I just added a custom button to each project page. It maybe would be better if I handled that in the layout checking for the url.

It might be useful if I actually make a project's index file. Where I don't filter them by featured.

Consider using a Breadcrumb for navigating the website. And maybe a "view more" button below the featured projects.

[espinosajuanma]

Done in hugo-migration branch