Depend on MathOpthInterface instead of JuMP.jl

[jkhamphousone]

Support for all ILP JuMP solvers to be added.

[nsajko]

I think the ideal approach is to depend on MathOptInterface.jl while being solver-agnostic. While Gurobi is an impressive piece of software, it can be prohibitive as a strong dependency.

[jkhamphousone]

That is a great idea, indeed, thank you a lot :) I never used directly MathOptInterface.jl yet, always JuMP, so I will learn it! If you want to participate in the development, do not hesitate 👍