feat: port DateAdjusters

[chrisimcevoy]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 98.56115% with 2 lines in your changes missing coverage. Please review.

Project coverage is 95.46%. Comparing base (033534f) to head (60908f0).
Report is 30 commits behind head on main.

Files	Patch %	Lines
pyoda_time/_local_date.py	89.47%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #150      +/-   ##
==========================================
+ Coverage   95.44%   95.46%   +0.02%     
==========================================
  Files         232      233       +1     
  Lines       18189    18319     +130     
==========================================
+ Hits        17360    17489     +129     
- Misses        829      830       +1     

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