Added more Scipy integrators to handle stiff problems

[mkaguer]

Currently there is only one scipy integrator classes that uses RK45. I created a general integrator class that uses RK45 by default called ScipyIntegrator, this is the parent class. Then, I created child classes that inherit from this class but pass different solvers. I added two more solvers currently not available, BDF and LSODA. These solvers work for stiff problems.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 89.8%. Comparing base (7c45c22) to head (d5ab2f0). Report is 9 commits behind head on dev.

Additional details and impacted files

@@          Coverage Diff          @@
##             dev   #2880   +/-   ##
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  Coverage   89.7%   89.8%           
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  Files        148     148           
  Lines       8660    8670   +10     
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+ Hits        7776    7786   +10     
  Misses       884     884           

[mkaguer]

Nice, can you add some unit tests?

Yea, I'll do that this week when I get back to work!

[mleot]

I also have motivation to add more integrators to OpenPNM. I can help out with writing some of these unit tests.