[ENHANCEMENT] Statistical analysis of structural parameters

[sanghamitra-mukhopadhyay]

It would be good to have some statistical analysis, such as distributions of structural parameters, which MDANSE already calculates be available as data file and workspace for plotting against parameter values.

These parameters will may be

1. interatomic distances, such as H-O, Si-Si, or Si-O etc
2. interatomic angles, such as Si-O-Si, O-H-O etc.
3. dihedral angles, such as H-O-H-O etc
4. coordination numbers, such as 2-coordinates Si, three coordinated Si etc.

Following papers can be consulted. Input files will be available.

AIP Conf. Proc. 1969, 030001 (2018)
Phys Rev. B 71, 235204 (2005)