feat: 2D config preset table

[tlambert03]

proof of principle of the 2D table that @marktsuchida was describing in #307 (comment)

would still need:

• ability to add a new row (a new dev/prop that all presets should set)
• ability to add/remove columns (to add/remove presets)
• editable column headers (to rename a preset)
• deal with jagged config groups (where not all presets have the same dev/props)

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 177 lines in your changes missing coverage. Please review.

Project coverage is 89.01%. Comparing base (1cda2b7) to head (92fb2f8).

Files with missing lines	Patch %	Lines
src/pymmcore_widgets/_config_preset_table.py	0.00%	177 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #320      +/-   ##
==========================================
- Coverage   90.71%   89.01%   -1.71%     
==========================================
  Files          85       86       +1     
  Lines        9234     9411     +177     
==========================================
  Hits         8377     8377              
- Misses        857     1034     +177     

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