Capture stenoses-like pressure losses in junctions

[JonathanPham]

Some junctions have large area changes that induce high pressure losses. An example of this is shown below.

An interesting idea that @mrp089 had to model these junction pressure losses in the 0D models would be to use the StenosisBlock formulation (but without the Poiseuille resistances) directly within a new StenosisJunction block.

I'll prototype this idea to see how well it works.