Add support for fractional coordinates

[oerc0122]

Description of work
Implement parsing of scaled positions in lammps.

Fixes
Fixes #1504

To test
New test attempting to force parsing of scaled positions

[oerc0122]

Kick tests

[MBartkowiakSTFC]

Thank you for the changes. Let's see what the tests do.

[oerc0122]

Kick tests

[alexhroom]

kick tests x2 (these poor tests...)

[alexhroom]

several tests failing due to a bug in _create_lammps_region:

    def _create_lammps_region(self, universe: Universe, region_ID: str) -> None:
        """
        Create a geometry of the simulation box in LAMMPS
    
        Parameters
        ----------
        universe : Universe
            The MDMC ``Universe`` used to create the region.
        region_ID : str
            The LAMMPS region ``ID``
        """
    
        xlo = ylo = zlo = 0.
>       xhi, yhi, zhi = universe.dimensions
E       AttributeError: 'NoneType' object has no attribute 'dimensions'

[alexhroom]

error mentioned above still seems to be present, just marking as request changes for bookkeeping