Major package refactor

[emmanuellujan]

Package refactor integrating the code of the following sources:

• Latest developments in atomistic composable worflows: https://github.com/cesmix-mit/AtomisticComposableWorkflows/tree/master/ACE
• Active learning branch: https://github.com/cesmix-mit/PotentialLearning.jl/tree/active_learning_refactor
• Old refactor branch: https://github.com/cesmix-mit/PotentialLearning.jl/tree/refactor

[emmanuellujan]

First refactoring iteration done. See https://github.com/cesmix-mit/PotentialLearning.jl/pull/20

Goal:

• Gather all functions related to the learning process in this package.
• Based on these functions, and the old interfaces, generate the abstractions that we really need.

Currently I am gathering the functions associated with the branch refactor. This branch facilitates the development of the case studies in https://github.com/cesmix-mit/AtomisticComposableWorkflows.

Next, the functions associated with the branch active_learning_refactor will be integrated.