Review current gas formulation in SpineOpt to see if it is possible to get rid of the BigMs there

[datejada]

Is your feature request related to a problem? Please describe.
Current gas flow formulation uses BigM constants that lead to bad solutions if they are selected correctly.

Describe the solution you'd like
Review the current formulation and check alternative formulations to either use one without BigMs or determine the value BigM should get more efficiently.

Describe alternatives you've considered
One starting point is this paper:
https://optimization-online.org/wp-content/uploads/2014/10/4580.pdf

Additional context
double-check more recent works on this topic.

[datejada]

@g-moralesespana, We might want to use some of the findings we got from Thomas' research. Any thoughts?

[nnhjy]

This paper looks useful as well
https://doi.org/10.1016/j.segan.2022.100990

I kinda know the author and may contact the guy for help.