nonlinear-programming

The same user as #2662 asked for ways to solve a collection of problems over a set of parameters. We don't have a good way of doing this in JuMP (we have @NLparameter, but not @parameter), but it could be scripted using the modification API (or even just rebuilding the problem).

We should write a tutorial with the different approaches. Here's their suggestion:

![image](https://user-image

The basics of DiscreteSystem exists now, but the little details around it need to be finished.

Something like

Execution stats:
 - Status: ...
 - Dual measure: ...
 - Primal measure: ...