v0.6.1 Improved pipeline processing

• More Ruff linting and type hinting
• Reorganize util into more submodules to avoid circular dependencies.
• #27 Added ApFitsRasterizer and CLI ap_fits_rasterizer, with only
  the stiff backend currently.
• #27 Added plot_stiff_threecolor and make_stiff_threecolor_plots
  to ApUtil.
• #27 ApProcessor will generate TIFF format quick look image of resampled output.
• #27 ApProcessor can skip regenerating already preprocessed images.
• #27 Fix bug introduced into ApMasterCal when linting.
• #27 Add option to ApProcessor to allow different swarp COMBINE_TYPE when
  resampling, in particular allow MEDIAN instead of WEIGHTED. MEDIAN strongly
  reduces residual hard-to-correct CR noise but increases background noise
  levels by 60%, and requires input images are similar in exposure time
  (and maybe pixel scale and coverage).
• #32 Improve summary plot generation for multi-degree wide images.
• #32 Better handing of cases where no candidates can be fitted in
  ApMeasureStars and ApFindStars, with helpful error messaging.
• #32 Include nearest neighbor distance estimate in fit box size calculation.
• Added patching_holes_from_bad_flats.ipynb
• Split make_dothead_from into file, keywords, wcs options
• Fix summarize_wcs when there is a PC?_? matrix.
• #31 Added ApFixHoles to fill in larger scale user-defined holes.
• #28 Added option to exclude source detection at the corners of images.