Revisit implementation of explicit solvent environment

[yjmaxpayne]

The solvent environment plays an important role, as shown in this early use case example for drug discovery A Quantum Computing Pipeline for Real World Drug Discovery: From Algorithm to Quantum Hardware As shown in Table I of the paper. The associated repo of the work is this one: https://github.com/AceMapAI-Biotech/qc-drug-design

I would suggest the team to consider this as some new features we should implement.

A reference work could be this one: https://github.com/davidecast/PCM-VQE