phaseplot widget, export layers to yt ds

[chrishavlin]

This PR adds:

• a convenience function for exporting layers loaded in napari to a uniform grid yt ds
• a new phaseplot widget

may split those to separate prs...

[codecov]

Codecov Report

❌ Patch coverage is 99.19137% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 99.55%. Comparing base (eb16ab0) to head (d27faa7).
⚠️ Report is 49 commits behind head on main.

Files with missing lines	Patch %	Lines
src/yt_napari/_widget_2d_plots.py	98.52%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #152      +/-   ##
==========================================
- Coverage   99.60%   99.55%   -0.05%     
==========================================
  Files          37       40       +3     
  Lines        2799     3170     +371     
==========================================
+ Hits         2788     3156     +368     
- Misses         11       14       +3     

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[chrishavlin]

Still needs a bunch of UI design and fixes:

• labels (those drop downs are the PhasePlot x, y, z and weight field arguments
• add options for the rest of the PhasePlot arguments
• add some options for plot callbacks (log switches, colormap, etc)
• the matplotlib figure does not rescale well with the window

but there's a figure!

[chrishavlin]

pre-commit.ci autofix

[chrishavlin]

latest push adds some callbacks, but at present it needs to fully re-render