add several ID solvers

Different solvers exist for IDs and related diagrams and we may want to use a specific solver for a specific type of problem. For example, pyagrum solves for soluble LIMIDs, DecisionProgramming implement the possibility to add constraints and minimize CVar instead of maximizing MEU, DANs may require a specific solver ...

As there is no unique representation of all problems, a solution could be to expose the different representation and possible solvers for each of them.

Start by cataloguing the problem representations and solvers named in the issue, including pyagrum, DecisionProgramming, LIMIDs, DANs, and IDs. Determine how the API should expose valid solver choices for each representation and define completion as supporting the agreed solver-selection model without assuming a single representation for every problem.

Written by the indexing model from the issue text.