Consider support for Python DCM

[maedoc]

Describe the new feature or enhancement

A Pythonic wrapper for DCM was created https://github.com/roschkoenig/Pythonic-DCM, we can consider wrapping it or generating TVB model code for interfacing with the algorithms there.

Describe your proposed implementation

DCM can work with Jacobians, so generating a MATLAB function computing the Jacobian would be an easy way. Another route would be generatign a MATLAB function to compute the full nonlinear gradients for the system.