ZEP1: Apply review feedback for terminology section

[jstriebel]

This PR applies some feedback from the ZEP1 review in #149. It adds illustrations to the terminology, and improves the store and storage transformer sections. In detail:

• Added two illustrations, one for the general hierarchy and array terminology, and one for the codec/array/storage transformers/store workflow. Both were made with https://excalidraw.com. The png files include the source and can be loaded into excalidraw for further editing.
• Added examples to store terminology section, as requested in
  ZEP0001 - Core v3.0 spec for review #149 (comment)
• Improved the storage transformer terminology section, as requested in
  ZEP0001 - Core v3.0 spec for review #149 (comment)
• Reordered the terminology definitions slightly, to fit better to the illustrations
  (moved codec and compressor more to the end, after the second illustration).

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Screenshots of the rendered specs with the illustrations

(The changes from the ZEP1 review were applied to the main branch for the screenshots)

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[jstriebel]

This PR replaces the original PR alimanfoo#1, as we discussed to gather all PRs here onto the main branch (see #149 (comment)).

[joshmoore]

• "Added two illustrations": 👍 and in general 💯 for any visual material since it helps the reader. (Downside will be keeping it in sync long-term)
  • "The png files include the source" Interesting!
• Added examples to store terminology section 👍
• Improved the storage transformer terminology section 👍
• Reordered the terminology definitions slightly 👍

There's still a large re-reading outstanding from my side, but I don't see a reason not to get these in.

[rabernat]

I think this is excellent, particularly the drawings. Thanks so much @jstriebel for these additions, which make the spec much more clear.

I have some minor editorial suggestions.

[MSanKeys963]

Thanks for sending this PR, @jstriebel.
The illustrations are excellent, and the text looks clear to me. I have one minor feedback:

If I try to view the illustrations here, I can't view them properly. This is because they don't have a background colour.
Should we add the illustrations with white background?

PS. I don't have a strong opinion on this, as I know these illustrations can be viewed on the web browser just fine. It's just the .md file.

[jstriebel]

If I try to view the illustrations here, I can't view them properly. This is because they don't have a background colour.
Should we add the illustrations with white background?

@MSanKeys963 Good point, next time I'll add the white background, but I'd leave it as-is for now for simplicity.

[joshmoore]

next time I'll add the white background, but I'd leave it as-is for now for simplicity.

Unless we eventually enable dark mode for the specs as well ;)