Add lattice thermal conductivity

[ElliottKasoar]

(Requested by potential user from MCC)

Currently, we use the Phono3py code for this purpose. Our typical workflow involves generating displaced structures using the command of phono3py -c CONTCAR -d --dim="x x x", followed by running single-point calculations for each structure using the attached script. We then extract the 3rd-order force constants from the resulting vasprun.xml files, which are used to compute the lattice thermal conductivity. More detailed info can be found at: https://phonopy.github.io/phono3py/

While Phono3py performs well across various systems, it becomes computationally demanding when applied to very large systems. Therefore, it would be highly appreciated if similar functionality could be implemented within janus-core, which could potentially offer better efficiency or scalability.

[alinelena]

we will need to look at the api and see what we want to inmplement
https://phonopy.github.io/phono3py/phono3py-api.html