Good morning, I am attaching the complete link of the project.

I comment that I present problems for the DATATABLE,
bootstrap-maxlength.html and recently with vis-timeline
I had to manually add in plugin.scss the following @import "~ vis-timeline / dist / vis-timeline-graph2d.min.css";

and in js add require ('vis-timeline / dist / vis-timeline-graph2d.min.js');

and Select2

I do not know if it is correct, do it like this?

The main detail is that it doesn't load the styles correctly and in the js files,
I have to manually call them in each .js
adding require('datatables.net');