Add APIs for decoder pipeline in QECCore

[nzy1997]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 98.21429% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 85.39%. Comparing base (11dd3e5) to head (139f73f).

Files with missing lines	Patch %	Lines
lib/QECCore/src/decoding_impl.jl	98.21%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #593      +/-   ##
==========================================
+ Coverage   85.32%   85.39%   +0.06%     
==========================================
  Files         123      124       +1     
  Lines        7504     7560      +56     
==========================================
+ Hits         6403     6456      +53     
- Misses       1101     1104       +3     

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[nzy1997]

@Krastanov This PR is ready for review when you have time. Thanks!