Add constraints list of an intersection of polytopes

[mforets]

Add constraints_list(Intersection(::AbstractPolytope, ::AbstractPolytope), which is just the concatenation of the constraints of each argument. We could optionally remove the redundant constraints, or leave that as an option for later.

julia> using LazySets

julia> using Polyhedra

julia> rand(HPolytope)
HPolytope{Float64}(LazySets.HalfSpace{Float64}[HalfSpace{Float64}([-0.0159433, -0.35622], 0.297744), HalfSpace{Float64}([-0.216196, -0.316775], -0.0149291), HalfSpace{Float64}([0.107764, 0.210512], 0.0259863)])

julia> constraints_list(rand(HPolytope) ∩ rand(Hyperrectangle))
ERROR: MethodError: no method matching constraints_list(::Intersection{Float64,HPolytope{Float64},Hyperrectangle{Float64}})
Closest candidates are:
  constraints_list(::LazySets.HalfSpace{N<:Real}) where N<:Real at /Users/forets/.julia/dev/LazySets/src/HalfSpace.jl:244
  constraints_list(::AbstractHyperrectangle{N<:Real}) where N<:Real at /Users/forets/.julia/dev/LazySets/src/AbstractHyperrectangle.jl:80
  constraints_list(::AbstractHPolygon{N<:Real}) where N<:Real at /Users/forets/.julia/dev/LazySets/src/AbstractHPolygon.jl:153
  ...
Stacktrace:
 [1] top-level scope at none:0

[mforets]

to do this, i think that we should rather refactor remove_redundant_constraints! to receive a list of constraints, so it can be used more generally.

[schillic]

I would still have it the way it exists now. But we can offer a second method.