Fixes #4916: clean CSS and JS resources declaration and use minified

Mainly, that commit centralize ALL JS/CSS resources declaration in common-layout.html, remove them from elsewhere, and use minified version when possible. 

Datatable case is bad: we can't use the minified version which leads to an error, but it would be one the most interesting gain (from 360ko to 70ko - or even 18ko for the gzip version).