[articles][vm-design] Add Spanish translation

Add the Spanish translation for the vm-design article.

Most of the work was done with Weblate[1]

Reviewed by: 0mp, carlavilla
Approved by: 0mp (mentor)
Differential Revision: https://reviews.freebsd.org/D29646

[1] https://translate-dev.freebsd.org/projects/documentation/articlesvm-design_index/es/