Feature : deepks_out_labels = 2 for label preperation in deepks training

[xuan112358]

What's changed?

• Modify unit of output deepks *.npy from Ry to Hartree, which is consistent with deepks-kit
• Enable deepks_out_labels as 2. When deepks_out_labels equals 2, all needed lable files are output with deepks prefix, including atom.npy, box.npy, energy.npy, as well as force.npy, stress.npy, orbital.npy, hamiltonian.npy, overlap.npy when specified. The units and formats are the same as label files required for training, except that the first dimension (nframes) is excluded. No-use files are not output. This can simplify deepks label preperation with ABACUS.
• Doc for deepks_out_labels = 2

How to use?

If you want to get deepks labels at the level of HSE:

• Do SCF calculations with dft_functional=hse and deepks_out_labels=2. If properties other than energy is needed, set cal_force for force label or deepks_v_delta for Hamiltonian label, etc.
• All needed file are output in the OUT.suffix folder. Concatenate files from all different configurations and remove the deepks prefix. Then you get the labels.
• System structrue files atom.npy and box.npy are also output in the unit of Bohr, which means lattice_constant should be set to 1 in scf_abacus.yaml when training with deepks-kit.

Unit Tests and/or Case Tests for my changes

• An Integration test is added