New easycore support

[rozyczko]

Migrated EasyCrystallography
from the old corelib architecture (ObjBase, CollectionBase) to the new
architecture (ModelBase, ModelCollection, CalculatorFactoryBase).

Current Architecture (Before Migration)

ObjBase (corelib - deprecated)
├── Lattice (Components/Lattice.py)
│   └── PeriodicLattice
├── Site (Components/Site.py)
│   └── PeriodicSite
├── AdpBase (Components/AtomicDisplacement.py)
│   ├── Anisotropic
│   ├── Isotropic
│   ├── AnisotropicBij
│   └── IsotropicB
├── AtomicDisplacement (Components/AtomicDisplacement.py)
├── SpaceGroup (Components/SpaceGroup.py)
├── MSPBase (Components/Susceptibility.py)
│   ├── Cani
│   └── Ciso
├── MagneticSusceptibility (Components/Susceptibility.py)
└── Phase (Structures/Phase.py)

CollectionBase (corelib - deprecated)
├── Atoms (Components/Site.py)
│   └── PeriodicAtoms
└── Phases (Structures/Phase.py)

Other Classes (no migration needed):
├── Specie (extends DescriptorStr)
├── Twin (plain Python class)
├── SymmOp (extends SerializerComponent)
├── SymmetryGroup/PointGroup/SpaceGroup (Symmetry groups - abstract/metaclass)
└── IO classes (template, parser, star classes)

Target Architecture (After Migration)

ModelBase (corelib - new)
├── BaseCore (new compatibility layer)
│   ├── Lattice
│   │   └── PeriodicLattice
│   ├── Site
│   │   └── PeriodicSite
│   ├── AdpBase
│   │   ├── Anisotropic
│   │   ├── Isotropic
│   │   ├── AnisotropicBij
│   │   └── IsotropicB
│   ├── AtomicDisplacement
│   ├── SpaceGroup
│   ├── MSPBase
│   │   ├── Cani
│   │   └── Ciso
│   ├── MagneticSusceptibility
│   └── Phase

ModelCollection (corelib - new)
├── BaseCollection (new compatibility layer)
│   ├── Atoms
│   │   └── PeriodicAtoms
│   └── Phases

[github-actions]

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