Reorg of the Usage section of the docs

[melissawm]

References and relevant issues

N/A

Description

At the napari hackathon @ gloBIAS, we had the chance to discuss the docs organization with a few users and came up with ideas for potential improvements to our Usage section. We also discussed some changes to our API docs, but those will be handled separately.

This is a first very rough draft that is clearly incomplete, but I wanted to stash it somewhere so the work can continue.

EDIT: This is now ready for review. It only touches the first sections of the user guide but I think this is reasonable for now. This was discussed at the docs meeting this week (nov 20/21).

[psobolewskiPhD]

This is really great! 😍
Huge fan of breaking out the Layers into its own thing! This PR is the real closer to #42 😉

One thing that stand out to me:
Getting started > Open images is empty -- just a placeholder for now? Maybe we should copy paste something into it and flag it as a followup?
(the quickstart open an image could use a spruce up too probably)

[brisvag]

Love this work @melissawm! Much better than main :) Some thoughts:

• Did we come up with a better name for the Features highlights section in the end?
• I'd rename napari tutorial to something like case studies or in depth examples or walkthroughs. I'm also not sure if we want that there or lower down, but maybe we already discussed this?

[DragaDoncila]

as mentioned in docs meeting, I love this reorg ❤️ I dropped by because I noticed in the napari help menu we link to some of these guides, and I wanted to flag it in case we need to update any of those URLs. I don't think we do? Because it looks like it links to the file and we don't move the file. But just wanted to flag it and ask.