[Dev] Tutorial for constraints at intermediate times

[ocots]

Add a tutorial about handling constraints at intermediate times.

See this example.

See also control-toolbox/OptimalControl.jl#482.

[jbcaillau]

could be performed on the abstract code

[ocots]

Yes indeed. We are not compelled to wait that this feature exists to add an example. The example will permit to show how to do it now. We will update it when possible.

[jbcaillau]

by doing it at the abstract level i do not mean write a use case and the associated syntax; i mean implementing the feature a transformation on the source code, from an abstract OCP model towards and another.

[ocots]

Ok I see, it is two independent things.