chore(architecture diagrams): add C4 diagrams

[Bai-Li-NOAA]

What is the feature?

• add a C4 system context diagram to present the ecosystem simulation toolkit: {ecosystemom} and {ecosystemdata}

How have you implemented the solution?

• Add a mermaid flowchart to architecture_diagrams/system_context_diagram.md
• Add /architecture_diagrams folder to .Rbuildignore
• TODO: ideally, an arrow should connect DSEM and the stock assessment models. However, it's unclear how to force a clean left-to-right layout in Mermaid. The approach I tried results in a cluttered diagram.

Does the PR impact any other area of the project, maybe another repo?

• Once merged into main, @Bai-Li-NOAA will update the {ecosystemdata} README to include a link to the diagram.

[kellijohnson-NOAA]

@Bai-Li-NOAA gemini helped me figure out how to get rid of the titles in the subgraph, it is expecting a string not ""\n so if you replace the string with "" but add a space before the return then it will render without a subgraph title.

[kellijohnson-NOAA]

I tried to get the link between DSEM and SA but like your trials and tribulations I was unable to make it happen without changing the entire structure of the diagram. But, I do not think that we need all three external systems in the separate box, especially EWE models with DSEM and SA. I think that the legend helps define what they are and they do not need to be grouped together.
Also, I am unsure why some lines are dashed and some are solid.

[kellijohnson-NOAA]

Suggested change

	This diagram presents the ecosystem simulation toolkit at the center, surrounded by its users and the external systems
	This diagram presents the ecosystem-simulation toolkit at the center, surrounded by its users and the external systems

[kellijohnson-NOAA]

I would prefer to take out the -<i>Person<\i> from each of these lines because it is clear from the legend that it is a "person" and it would allow for more room for the diagram. Same for -<i>External System</i>- on lines 43--35.

[kellijohnson-NOAA]

Can we list EWE and Atlantis here instead of "External System"?

[kellijohnson-NOAA]

Does mermaid have the ability to provide a hyper link to the DSEM repository with the text here?

[kellijohnson-NOAA]

Can we list example models here like FIMS with a hyperlink instead of "External System"?

[kellijohnson-NOAA]

I do not quite understand what you are trying to imply with "Provides functions to connect with external tools to perform time series analysis"

[kellijohnson-NOAA]

Suggested change

	EcosystemOM[<b>ecosystemom</b><br/><br/> -<i>R package</i>-<br/><br/> Samples observations from ecosystemdata for stock assessment testing]:::lightgreen
	EcosystemOM[<b>ecosystemom</b><br/><br/> -<i>R package</i>-<br/><br/> Samples observations from ecosystemdata to fit to stock assessments]:::lightgreen