[BUG] Darts matplotlib style settings should be optional

[zgana]

Describe the bug
Importing anything from darts results in significant changes to the global matplotlib configuration. The style is pretty good, but it should be optional.

To Reproduce

import matplotlib.pyplot as plt
import darts
plt.figure()

Expected behavior
There is a way to make the figure reflect the user's personal matplotlibrc without manually undoing everything listed in darts/__init__.py.

System (please complete the following information):

• Python version: 3.7.9
• darts==0.17.1

Additional context
A possible fix would be to suppress this call if something like export DARTS_CONFIGURE_MATPLOTLIB=0 is set.

[hrzn]

Agree. Would you be willing to work on such a fix?

[zgana]

@hrzn Yes. Does this need to be added to the project board or should I go straight to submitting a PR?

Edit: I see now that it was automatically added to "To do". Should I mark it "In progress" or just focus on the PR?

[hrzn]

@zgana, I just moved it to "in progress". Feel free to focus on the PR and open it once it's ready. Let me know if you have any question. Here are our contribution guidelines. Don't forget to add an entry to the change log :)

[swertz]

I was looking for a way to avoid this global style change when importing darts, and I'm happy to see that there is a way to disable it. However, I think the better solution would be to have darts produce all plots whithin a context manager. This way, darts-produced plots could still follow the darts style (unless disabled by the DARTS_CONFIGURE_MATPLOTLIB=0, but without affecting the style chosen by the user.

If you think this is acceptable, I could look into making a PR.