Migrate Optimal Transport to the intro Series

[HumphreyYang]

The optimal transport is closely related to the linear programming.

Should we consider migrating the optimal transport lecture to the intro series?

[mmcky]

Another idea is to use a seelaso admonition to link the two between lecture series.

[jstac]

+1 for @mmcky 's idea. Can someone please implement and close this issue?

[shlff]

Cool I'd love to take this one.

I will push a PR tomorrow after the presentations to add cross-links in these two lectures.