Allowing multiple properties in the same run

[mikibonacci]

• multiple spectra wanted: needed two simulation for dielectric tensors.
• multiple phonon properties: more phonopy calculations at the end of the phononworkchain (or harmonic one)
• multiple dielectric tensors.

==> we should introduce this logic in the VibroWorkChain, I think.

SelectMultiple in togglebuttons.

[mikibonacci]

After some investigation, I understood that the problem is that the output phonopy.yaml file does not contain the force sets, needed to compute the force constants. The input one, which is then overridden, contains them, and is written using a method of the PhonopyCalculation. These force sets can be written in output by setting in the phonopy inputs the INCLUDE_FS=.TRUE. flag.

However, I will try to write also the force constants in the output yaml, so I can use it also within Euphonic (which reads Force constants computed with phonopy). I will do this using the INCLUDE_ALL=.TRUE. flag.

[mikibonacci]

Within Euphonic, it is possible to compute very easily bands, dos and pdos. Only thermodynamic observables are left out, and can be computed with phonopy. So, we can let these properties to be interactively computed in the output section of the app.

We should keep separated the simulation of Raman and IR, as we are using Gamma point sampling there. This should be specified in the app settings.