chore: move secret ignoring logic inside the scanner

[gg-mmill]

Context

Currently, there are logic related to ignoring secrets in two places:

• in the secret scanner
• in the output handlers

What has been done

Move all the logic to the scanner:

• "ignore known issues" now works in the same way than other ignore featues
• Result objects now contain the list of PolicyBreaks (instead of ScanResult), as well as a dictionary containing the counts of ignored PolicyBreak by reason
• As a result, there is no more result filtering in output handlers - they can still access the options and count of ignored issues if needed

Validation

Need to add tests for the scanner Done
Will also perform some manual validation

PR check list

• As much as possible, the changes include tests (unit and/or functional)
• If the changes affect the end user (new feature, behavior change, bug fix) then the PR has a changelog entry (see doc/dev/getting-started.md). If the changes do not affect the end user, then the skip-changelog label has been added to the PR.

[codecov]

Codecov Report

Attention: Patch coverage is 98.36066% with 1 line in your changes missing coverage. Please review.

Project coverage is 92.03%. Comparing base (eb51582) to head (4fb68d1).
Report is 11 commits behind head on main.

Files with missing lines	Patch %	Lines
...ticals/secret/output/secret_text_output_handler.py	90.90%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1016      +/-   ##
==========================================
- Coverage   92.08%   92.03%   -0.05%     
==========================================
  Files         181      181              
  Lines        7728     7706      -22     
==========================================
- Hits         7116     7092      -24     
- Misses        612      614       +2     

Flag	Coverage Δ
unittests	92.03% <98.36%> (-0.05%)	⬇️

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[agateau-gg]

Minor remarks, but this looks much cleaner! ✨

[agateau-gg]

Minor remarks.

[gg-mmill]

Thanks for the review !
About the ignoring, I had to change what I did here when implementing the all-secrets option (future MR, not ready yet): separate the computation of the ignore reason, and the actual ignoring, see https://github.com/GitGuardian/ggshield/pull/1024/files#diff-37638c3845d9f616b7031dec851a57324bec777285097c841b887d2a1f9dd34eR236

[agateau-gg]

Looks better now, thanks for this work!