feat: Make SourceLink SBO size configurable via CMake

[paulgessinger]

This PR allows customizing the SBO size that SourceLink uses. We default to a sort of generous 16 bytes, and clients might want to reduce this.

[codecov]

Codecov Report

Merging #2357 (b63e2b7) into main (0f745ae) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #2357   +/-   ##
=======================================
  Coverage   49.63%   49.63%           
=======================================
  Files         453      453           
  Lines       25530    25530           
  Branches    11705    11705           
=======================================
  Hits        12672    12672           
  Misses       4579     4579           
  Partials     8279     8279           

Files Changed	Coverage Δ
Core/include/Acts/EventData/SourceLink.hpp	87.50% <ø> (ø)

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[github-actions]

📊: Physics performance monitoring for b63e2b7

Full contents

physmon summary

• ✅ Ambisolver orthogonal
• ✅ Ambisolver seeded
• ✅ Ambisolver
• ✅ AMVF orthogonal
• ✅ AMVF seeded
• ✅ AMVF truth_estimated
• ✅ AMVF truth_smeared
• ✅ AMVF ttbar
• ✅ CKF orthogonal
• ✅ CKF seeded
• ✅ CKF truth_estimated
• ✅ CKF truth_smeared
• ✅ CKF ttbar
• ✅ Truth tracking (GSF)
• ✅ IVF orthogonal
• ✅ IVF seeded
• ✅ IVF truth_estimated
• ✅ IVF truth_smeared
• ✅ Particles final fatras
• ✅ Particles final geant4
• ✅ Particles inital fatras
• ✅ Particles inital geant4
• ✅ Seeding orthogonal
• ✅ Seeding seeded
• ✅ Seeding truth_estimated
• ✅ Seeding ttbar
• ✅ Track Summary CKF orthogonal
• ✅ Track Summary CKF seeded
• ✅ Track Summary CKF truth_estimated
• ✅ Track Summary CKF truth_smeared
• ✅ Truth tracking

[andiwand]

one question - otherwise good to go IMO

[acts-project-service]

✅ Athena integration test results

✅ All tests successful

status	job
🟢	run_unit_tests
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsWorkflow.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateTracks.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateActsCoreSpacePoints.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateActsSpacePoints.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateSeeds.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateOrthogonalSeeds.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateClusters.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsPersistifyEDM.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsKfRefitting.sh
🟢	run_ci_tests: python3 ../athena/Tracking/Acts/ActsGeometry/test/ActsExtrapolationAlgTest.py
🟢	run_ci_tests: python3 ../athena/Tracking/Acts/ActsGeometry/test/ActsITkTest.py
🟢	run_workflow_tests_run4_mc
🟢	run_workflow_tests_run2_mc
🟢	run_workflow_tests_run2_data
🟢	run_workflow_tests_run3_mc
🟢	run_workflow_tests_run3_data