Add DataType equal and all_equal helpers

[GDYendell]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 94.11765% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 90.82%. Comparing base (49e799e) to head (3fe06ff).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/fastcs/datatypes/datatype.py	90.90%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #289      +/-   ##
==========================================
+ Coverage   90.78%   90.82%   +0.04%     
==========================================
  Files          70       70              
  Lines        2473     2486      +13     
==========================================
+ Hits         2245     2258      +13     
  Misses        228      228              

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