Draft: Julia-based MACE interface for more efficient ring-polymer simulations

[Alexsp32]

Adds support for a model type that directly interfaces with MACE instead of using the ase interface in NQCModels.jl.

We can get a minor efficiency gain in ring-polymer calculations by batch evaluating bead structures in potential energy / derivative calls. This PR includes documentation updates for interfacing ML models with NQCDynamics.jl and a new calculator type to take advantage of batching in the MACE interface.

The MACE interface itself will be a PR to NQCModels.jl (link soon).