#51 Add option to overlap importance on train and test in plot of ShapModelInterpreter

[eduardo-lourenco]

This PR targets issue #51:

• Adds option to have ShapModelInterpreter plots for both train and test sets in the same graph.
• Updates the tutorial related with model interpretation.

I will update the related tests if this solution seems appropriate (current tests are still passing, we just need to add new tests).

[Matgrb]

@eduardo-lourenco Are you going to still work on this one PR?

[ReinierKoops]

hi @eduardo-lourenco thanks for your contributions, could you update your PR to be made compatible with the latest changes on main?

[ReinierKoops]

This PR is closed. Please reach out if you want to continue with this PR.