Add periods parameter to Diff primitive and add DiffDatetime primitive

[ozzieD]

• Fixes Add gap parameter to Diff primitive #1805
• Added periods parameter in Diff so we can shift the difference on time series data
• After discussing with team, we added a separate DiffDatetime primitive

[codecov]

Codecov Report

Merging #2155 (eb13d4c) into main (8a0d53f) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head eb13d4c differs from pull request most recent head e5117a1. Consider uploading reports for the commit e5117a1 to get more accurate results

@@           Coverage Diff           @@
##             main    #2155   +/-   ##
=======================================
  Coverage   99.23%   99.23%           
=======================================
  Files         143      143           
  Lines       17196    17230   +34     
=======================================
+ Hits        17065    17099   +34     
  Misses        131      131           

Impacted Files	Coverage Δ
...retools/primitives/standard/transform_primitive.py	100.00% <100.00%> (ø)
...s/tests/primitive_tests/test_transform_features.py	99.86% <100.00%> (+<0.01%)	⬆️
featuretools/tests/entityset_tests/test_es.py	100.00% <0.00%> (ø)
featuretools/tests/selection/test_selection.py	100.00% <0.00%> (ø)
featuretools/tests/utils_tests/test_gen_utils.py	100.00% <0.00%> (ø)
...aturetools/tests/primitive_tests/test_agg_feats.py	99.51% <0.00%> (ø)
...uretools/tests/entityset_tests/test_es_metadata.py	100.00% <0.00%> (ø)
...retools/tests/primitive_tests/test_feature_base.py	100.00% <0.00%> (ø)
...ools/tests/primitive_tests/test_direct_features.py	100.00% <0.00%> (ø)
... and 9 more

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[gsheni]

Are we good to merge this? Or would you like another review?

[ozzieD]

Are we good to merge this? Or would you like another review?

I'm in the middle of updating this now since we came to the conclusion that it needs to be a separate primitive.

[tamargrey]

Small comment about the api reference, but other than that, looks good!

[tamargrey]

lgtm!