Aiida-vasp

**Added**
\- Allow Structures which do not have sites of same element grouped

- Allow using different potentials for atoms of same element in a structure
- `VaspCalculation`'s `settings` input now accepts `poscar_precision` key to set maximum precision for coordinates in POSCAR
- This can be indicated in the structure by adding sites with same `symbol` but different `name`.
- `io.poscar.PoscarIo`, POSCAR writer replacing pymatgen one, to be replaced by parsevasp.

**Changed**
\- Use always the same order for species in POSCAR and POTCAR
\- POSCAR float precision default changed to 10 decimal places

**Added**
\- `data.potcar.PotcarData` (`vasp.potcar`) & `data.potcar.PotcarFileData`, replacement for PawData

- `PotcarData` is shareable, holds no licenced data

- `PotcarFileData` holds the licenced POTCAR file

- `io.potcar.PotcarIo`, handle conversion between File and DB representation of POTCAR information

- `io.potcar.MultiPotcarIo`, handle concatenation and splitting of POTCAR files containing multiple potentials

- `verdi data vasp-potcar`, CLI for importing and exporting POTCAR files

- `uploadfamily`, loads a set of POTCAR files into the db
- `exportfamily`, creates a compressed archive of POTCAR files in a family
- `listfamilies`, list existing POTCAR families

- `io.outcar.OutcarParser`, parses some information from OUTCAR file

- `calcs.VaspCalculation` and descendants

- inputs: `settings:ParameterData` additional settings that are not passed to VASP but to parsers etc

**Changed**
\- `calcs.VaspCalculation` and descendants

> - inputs: `paw:PawData` -> `potentials:PotcarData`

- `parsers.vasp.VaspParser`, redesigned

- parses OUTCAR too (or tries to)
- takes `parser_options` that can be given in the `settings` input in a `VaspCalculation`

- renamed `data.paw.PawData` -> `data.paw.LegacyPawData`

- `LegacyPawData` can not be stored or changed (read-only)

**Removed**
\- `io.potcar.PawParser`

**Deprecated**
\- `PawData` is deprecated and has been renamed `LegacyPawData`, it can be used to read `PawData` database objects.

Baseline