Add Normative Mineralogy feature

[elphick]

Composition is "the way in which a whole or mixture is made up." This can be in terms of chemistry or minerals.
The early development of the package has focused purely on chemistry, as provided by the user as an input.

It is intended that mineral content can be provided in the same way, but also by inference from the chemistry. Estimating mineral composition from chemical assay is known as Normative Mineralogy.

This package depends on a package called periodictable which has knowledge of elements, standard elemental codes, elemental mass and compounds. The idea is to create a similar reference for minerals and leverage the periodtable information to create a routine that can solve for minerals given a) chemistry, and b) selected minerals.

To do this we'll need a reference table of minerals. This will bring with it the advantage of standard mineral codes, similar to chemistry.

[elphick]

Thanks to BenFGA for the mineral reference resource: https://rruff.info/ima/