Documentation: Limited Area Modeling

[JPXKQX]

This PR includes an future version for the documentation up to the point including the following changes:

• Limited Area graphs
• Stretched graphs

The folder and file layout is planned to include more content in some categories in the future.

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📚 Documentation preview 📚: https://anemoi-graphs--42.org.readthedocs.build/en/42/

[mchantry]

Really like the docs, what do you think about specifying the number of nodes/edges at different refinement levels for the icosahedral approach?

Refinement 0 1 2 3 4 5 6
Num Nodes 12 42 162 642 2,562 10,242 40,962
Num Faces 20 80 320 1,280 5,120 20,480 81,920
Num Edges 60 240 960 3,840 15,360 61,440 245,760
Num Multilevel Edges 60 300 1,260 5,100 20,460 81,900 327,660

[HCookie]

Is there any blockers to merging this to improve the docs?

[mchantry]

Great work. Thanks.