General predict method for tasks

[laserkelvin]

This PR adds a base predict method to tasks, which is intended to be used for inference workflows. This method acts as a wrapper for the task forward call, but includes the additional step of applying the inverse normalization to the outputs, so that they are rescaled appropriately.

A summary of changes:

1. The predict definition in BaseTaskModule, which is inherited by all tasks except MultiTaskModule
2. Refactored the MultiTaskModule.ase_calculate to be predict, so that the interface is consistent. The workflow is more or less unchanged from before, but relies on subtask.predict.
3. For ForceRegressionTask, we override the predict logic slightly by rescaling both forces and node energies using the energy normalization factor if dedicated normalizers are not provided by those values separately.
4. Updated the ase calculator code to rely on the predict interface, regardless of whether it is multitask or not.

[melo-gonzo]

Looks good!