viz for leaf samples distribution

[tlapusan]

I would like to propose a new vizualisation type for leaf samples : by histrogram.
It is useful when you want to easily see the general distribution of leaf samples, instead of individual leaf samples.
More useful when there is a big tree with a lot of leaves and the bar plot vizualisation is hard to interpret.
For implementation, this will add another value ('hist') for display_type parameter from viz_leaf_samples function.
The new vizualisation will look like this :

• when we want to include a subset of leaf samples (when we want to exclude the outlier leaves, like that leaf with ±350 samples from above viz)

@parrt what do you think about it ?

[parrt]

Heh, looks pretty cool! I think it is useful. Let's add