Add a figure to document internal update dependencies

[nevrome]

This is only relevant from a developers perspective, but maybe the homepage is still the right place for it.

I imagine a table or a graph that documents which of our software tools potentially have to be updated if certain parts of the Poseidon schema are modified. For example: A change to the .ssf file specification is very important for trident and poseidon-eager, but not for the janno R package. It's not trivial to think this through, but I think it will help us to estimate the cost of certain operations and not forget about critical updates to our infrastructure.

[nevrome]

I added a first version of this in 66b0558. Will have to be adjusted and updated in the future, but I think it's already helpful.

https://poseidon-framework.github.io/#/dev_notes

[stschiff]

Love it. But I think we might want to add the web-server as well... or are the repositories meant to be also the actual web servers?

[nevrome]

I thought I had modeled that with the relationship "trident implements and uses the Web API, which serves the archives". Feel free to adjust it to your preferences. This mermaid syntax is super simple.