Migrate qiskit_nature.results

[mrossinek]

What should we add?

As part of #701, all existing modules of Qiskit Nature will be migrated.
This issue outlines the requirements for the existing results module.
This issue is blocked by #706.

⚠️ This migration needs to copy the code in order to abide the deprecation process!

Below are the current module contents:

qiskit_nature/
    results/
        BopesSamplerResult
        EigenstateResult
        ElectronicStructureResult
        LatticeModelResult
        ProteinFoldingResult
        VibrationalStructureResult

Here are the new locations for all of these classes.

qiskit_nature/
    second_quantization/
        problems/
            EigenstateResult
            electronic/
                ElectronicStructureResult
            lattice/
                LatticeModelResult
            vibrational/
                VibrationalStructureResult

Unittests should be migrated accordingly.

The classes BopesSamplerResult and ProteinFoldingResult can be ignored for the time being.

This will be updated later!