`EpwCalculation`: add support for PAW pseudos

The following code was a first attempt to also deal with PAW pseudos in the `EpwCalculation.prepare_for_submission` method:

```
remote_copy_list.append((
    parent_folder_ph.computer.uuid,
    Path(
    ph_path, outdir, '_ph0', '' if iqpt == 1 else f'{prefix}.q_{iqpt}', f'{prefix}.{fildvscf}_paw1'
    ).as_posix(),
    Path('save', f"{prefix}.dvscf_paw_q{iqpt}").as_posix()
))
```