linear_solver: Add methods getBInvARow, getBInvRow, getBInvACol, getBInvCol

[mkoeppe]

What language and solver does this apply to?
Linear Solver

Describe the problem you are trying to solve.
Access tableau information of simplex-based solvers

Describe the solution you'd like
API similar to https://github.com/coin-or/Osi/blob/master/src/Osi/OsiSolverInterface.hpp#L1985

Describe alternatives you've considered

Additional context
https://trac.sagemath.org/ticket/33493

[lperron]

Sorry, there is no way I can make that in a cross solver portable way.
We are not staffed for such an effort.