Fixes #4771: Rule grid, now stored as Json

http://www.rudder-project.org/redmine/issues/4771

All datas to describe the row in a datatable are now contained in a javascript variable.
all javascript is now in a javascript file so we don't mix lot of javascript/html in Scala code.

The Scala code is now dedicated to generate the javascript datas, and send them directly to a javascript function

In rudder-datatable.js we will be able to use reuse code and have DRY datatables.