Add WC for computing the isotherm in charged zeolites

[ltalirz]

This is a rebase of PR #28

[codecov-io]

Codecov Report

Merging #50 (13f87f3) into develop (e351569) will decrease coverage by 3.03%.
The diff coverage is 3.89%.

@@             Coverage Diff             @@
##           develop      #50      +/-   ##
===========================================
- Coverage    33.66%   30.62%   -3.04%     
===========================================
  Files           25       26       +1     
  Lines         2032     2263     +231     
===========================================
+ Hits           684      693       +9     
- Misses        1348     1570     +222     

Impacted Files	Coverage Δ
aiida_lsmo/workchains/zeoisotherm.py	0.00% <0.00%> (ø)
aiida_lsmo/calcfunctions/ff_builder_module.py	75.64% <90.00%> (+0.98%)	⬆️

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[danieleongari]

COMMENT
This PR implements a work chain specifically for charged zeolites. It is first adding a stechiometric number of counter ions, then running a number of Monte Carlo NVT simulation at high temperature to locate their optimal position and later runs the GCMC calculation for the adsorbate.

After some more experience with zeolite I don't think it is a wise idea to use this work chain because the equilibrations of the ions it is something you may want to do separately and widely test before running the isotherm.
Therefore, it is maybe better to split the first part and validate the protocol and the force field versus the experimental evidence for the location of the cations (available for a few well-known topologies).

I'm not deleting this PR so that who may be interested in such a study can take inspiration from this early work.