Replace supplier tree pdf with mermaid diagram

[ahouseholder]

Replace the PDF of the docs/howto/supplier_tree.md tree with a mermaid diagram.

Ideally, we'd have a tool that can generate the tree directly from python objects (perhaps as a feature of the policy generator?)

[j---]

Those PDFs are generated from LaTeX, specifically TikZ diagrams. There is already python that takes a CSV and generates the TikZ/LaTeX. Would it be easier to hook the TikZ into something suitable for the webpage or to re-write the workflow as from python objects to mermaid diagrams?

I will not say my python to TikZ workflow was ever super stable. Just pointing out there is already an intermediate diagram form to work with. See for example http://lukasschwab.me/blog/gen/blogging-with-tikz.html