Write minimisation with a dummy constraint function

[tkoskela]

Constraint function has a signiture of type function [C,CEQ,DC,DCEQ,parms] = EstimationConstraint1(x,logW,parms,data)

Objective function has been written in #71

Constrained minimisation algorithm should be in https://github.com/jump-dev/Ipopt.jl (something like the fmincon function in Matlab)

[tkoskela]

We need to dump JuMP and use the Ipopt C interface julia wrapper as previously discussed with Lars to allow passing complex objective and constraint functions

Useful links:

• CreateIpoptProblem docs
• Ipopt.jl C api

[tkoskela]

TODO:

• develop a simple(er) example before we merge WIP for constraint function #73
• get the gradient of the objective function with Enzyme