Add support for dynamic stratigraphy boundaries

Dynamic stratigraphy boundaries are now supported by allowing boundary values to be of type DynamicParameterization; subtypes of DynamicParameterization occurring in the Stratigraphy are evaluated and subsequently replaced by the resulting value at each step.

Also refactors the InputOutput module to include forcings and parameters, as one might expect.

The new CryoGridParams type serves a similar purpose as ParameterVector before but solves the problem of duplicate parameter values. This probably should have been done in a separate PR, but oh well.

Grid is also refactored to improve efficiency and allow for regridding via updategrid!.