Refactor Solver #2845
Description
Currently, amici::Solver is used to store all kinds of (mostly steady-state-related) options, that have nothing to do with the SUNDIALS solvers. We may want to clean that up as part of some major release.
Maybe in combination with restructuring ExpData for supporting time courses (#2450, #2452), so that different options can be specified for different periods.
Somewhat related to #2573.
Also, some other steady-state-related options are stored in amici::Model and don't really belong there either.