[dev] Pull accessioning out of samples

[StephenHulme]

The Sample model class is unweidly and accessioning logic is now better separated.

Changes proposed in this pull request

• Extract accessioning logic out of sample model into a concern
• Remove unused REXML imports
• Update rubocop todo

Instructions for Reviewers

[All PRs] - Confirm PR template filled
[Feature Branches] - Review code
[Production Merges to main]
    - Check story numbers included
    - Check for debug code
    - Check version

[codecov]

Codecov Report

❌ Patch coverage is 86.66667% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.18%. Comparing base (42f303e) to head (2f0308f).
⚠️ Report is 9 commits behind head on develop.

Files with missing lines	Patch %	Lines
app/models/sample_accessioning.rb	85.71%	8 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #5615      +/-   ##
===========================================
- Coverage    87.23%   87.18%   -0.05%     
===========================================
  Files         1460     1461       +1     
  Lines        33001    33003       +2     
  Branches      3470     3470              
===========================================
- Hits         28787    28773      -14     
- Misses        4193     4209      +16     
  Partials        21       21              

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[yoldas]

beautiful refactoring