Save only unique frames and use GIF frame durations from PIL

[stefmolin]

• Rather than creating an image for each frame, create one only for unique frames and then use PIL to set the duration for each frame when stitching together the GIF
• Refactored DataMorpher._record_frames() to just record and not advance the frame number
• Changed frame numbers in file names to iteration numbers
• Add frame_numbers parameter to stitch_gif_animation() for calculating durations
• Improve testing of stitch_gif_animation() to count frames and durations

Benefits:

• Significant reduction in file size of resulting GIF (~0.6 MB)
• Under one minute when just running a single job (music to heart in 53 seconds)
• ~10 second improvement per job from Run in parallel via CLI #273
  • The majority of which was the time it took for the progress bars to start showing progress → this was the time it took for the initial frames to be created before the morphing could even start
  • Progress also starts right away now

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.63%. Comparing base (81bcd6a) to head (30877fb).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #278      +/-   ##
==========================================
+ Coverage   98.58%   98.63%   +0.05%     
==========================================
  Files          81       81              
  Lines        2052     2056       +4     
  Branches      124      121       -3     
==========================================
+ Hits         2023     2028       +5     
  Misses         26       26              
+ Partials        3        2       -1     

Files with missing lines	Coverage Δ
src/data_morph/morpher.py	100.00% <100.00%> (ø)
src/data_morph/plotting/animation.py	100.00% <100.00%> (+2.43%)	⬆️
tests/plotting/test_animation.py	100.00% <100.00%> (ø)
tests/test_morpher.py	100.00% <100.00%> (ø)