Make it clearer how to pick specific MLIPs and do so in a future-proof manner

[Andrew-S-Rosen]

What new feature would you like to see?

The picking of MLIPs needs to be greatly overhauled to increase clarity. For instance, right now, if you pick method="m3gnet", but the user has no idea what version of M3GNet this is. Currently, it automatically picks "M3GNet-MatPES-PBE-v2025.1-PES", but what happens when a new version of M3GNet comes out? And what about if the user wanted r2SCAN instead? In general, it's not clear how to pick certain MLIPs at all. As another example, setting method="fairchem" will allow the user to select a fairchem model, but unless they are already familiar with the FAIRChemCalculator, they would not know that they need to pass name_or_path="uma-s-1p1" and task_name="omat" (for instance) as additional keyword arguments to select the model and task.

These are decisions that should be sorted out in general. This conversation mirrors that in https://github.com/materialyzeai/matcalc/pull/123.