Add "advanced pipeline", missing value, imputing module, maybe more

[lesteve]

So this is an ambitious goal, with some moving parts. We need to reevaluate depending on how fast we progress with other things.

This does not really fit in any existing module and this seems to long to put it in module 1.

Here are a few things that we could show:

• advanced pipeline: as currently in the wrap-up quiz 1. Need more details. I think it had to do with multiple levels of nesting inside the pipeline
• missue value imputing

[ogrisel]

Maybe we could present splines and dealing with time features in this module:

https://scikit-learn.org/dev/auto_examples/applications/plot_cyclical_feature_engineering.html

This will require scikit-learn 1.0 which is not released yet though.

[ogrisel]

I created a MOOC 3.0 milestone, to make it less of a priority that MOOC 2.0 which should primarily be focused on a improving the existing material. We can always re-milestone issues based on progress.