Implement the build workflow entirely based on node

[pietro909]

As of now, some gulp tasks are tied up in the Makefile with some tape and luck.

It would be nice to have the whole workflow just depending on Node (like npm tasks or Gulp or Grunt... you got the point).

Based on @boghy8823's feedback, after he tried to set up everything under Windows 🥇

[pietro909]

It could actually have much more sense to remove the Gulp part and keep everything in the Makefile: it just works.