Update old publications to Nimble-Builder page builder

[AleixMT]

Old publications in Wordpress were made with the default Wordpress editor. Those have some incompatibility with the newer publications that are built with Nimble Builder.

Our task will be to refactor the old publications in order to "move" them to Nimble Builder if possible.

These changes are not only functional, they are aesthetic since Nimble Builder produce a much cleaner, responsive and beautiful frontend pages.