[WIP] Function scaling

[cvanaret]

• [x] added Scaling class
• [x] added EvaluationSpace::compute_constraint_jacobian_norms() to compute the inf norm of each Jacobian row
• [x] created an optional scaling object in the constraint relaxation strategies
• [x] renamed scale_functions option into use_function_scaling
• [x] use objective scaling in the subproblem
• [ ] use constraint scaling in the subproblem

Fixes https://github.com/cvanaret/Uno/issues/425