refactor: Move byte utilities to core:common module

[jamesarich]

This commit moves the byteArrayOfInts and xorHash utility functions from core:model to a new, more appropriate core:common module.

This refactoring improves modularity by placing common byte manipulation utilities in a shared location, making them reusable across different parts of the application. The core:model module now depends on core:common to access these functions.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 0.52%. Comparing base (22513e4) to head (7f8c6ed).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
...ain/kotlin/org/meshtastic/core/common/ByteUtils.kt	0.00%	2 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #3977   +/-   ##
=====================================
  Coverage   0.52%   0.52%           
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  Files        394     395    +1     
  Lines      23172   23172           
  Branches    2944    2944           
=====================================
  Hits         122     122           
  Misses     23029   23029           
  Partials      21      21           

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