discrete choice modeling blogpost

[drbenvincent]

This PR adds a notebooks which will form the second Colgate client write-up blog posts.

The first post was Causal sales analytics: Are my sales incremental or cannibalistic?

NOTE: I'll be pretty aggressive about hiding most of the code cells in the final blogpost in order to maximise readability.

Current state: At this point (2024/10/31) I've basically written the first half of the blog post. It outlines the basic discrete choice model and sets up the core limitation of producing uninteresting cannibalization effects.

TODO

• [ ] We might want to play with the random seed to get the synthetic data nice
• [ ] We might also want to tweak the synthetic price data to allow for better parameter identiability
• [ ] Potentially add a manufacturer (or benefit) effect to really show the lack of interesting cannibalization effects.
• [ ] I'm hoping that either @ricardoV94 or @lucianopaz or @cluhmann will take over the reigns and continue the blog post to talk about the core innovations of what we did. We are allowed to talk about the maths of the nested logit, but we're not allowed to present code to implement it.
• [ ] Hoping someone can write a nice overview of the cool new stuff that was done. I'll then come back in and wrap it up with the executive summary at the start and a conclusion summary at the end.