BaseDistribution: Add naive .plot()

[hibukki]

Nothing fancy, just replace

samples = total_tuners_in_2022 @ 1000
plt.hist(samples, bins=200)
plt.show()

with

total_tuners_in_2022.plot()

I think more can be done here, like using Seaborn, but I tried keeping this PR simple and uncontroversial.

The old functionality is still supported, so this shouldn't break anything.

Regarding this: num_samples=None, bins=None, I decided to leave flexibility for the implementation to decide on the num_samples if the user defines the bins, and vice versa, but this isn't a strong opinion.

Fixes #4

[peterhurford]

Thank you!