[hist] Implement initial RProfile

[hahnjo]

It builds on RHistEngine with an additional variable.

[github-actions]

Test Results

    23 files      23 suites   3d 17h 37m 53s ⏱️
 3 876 tests  3 875 ✅ 0 💤 1 ❌
78 827 runs  78 826 ✅ 0 💤 1 ❌

For more details on these failures, see this check.

Results for commit 1defbd5.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

❌ Patch coverage is 99.23077% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 59.83%. Comparing base (e39fc3f) to head (311c361).
⚠️ Report is 11 commits behind head on master.

Files with missing lines	Patch %	Lines
hist/histv7/inc/ROOT/RProfile.hxx	99.14%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #22588      +/-   ##
==========================================
+ Coverage   59.81%   59.83%   +0.02%     
==========================================
  Files        3369     3370       +1     
  Lines      495685   495978     +293     
  Branches    95189    95186       -3     
==========================================
+ Hits       296470   296754     +284     
- Misses     199215   199224       +9     

Flag	Coverage Δ
unittests	59.83% <99.23%> (+0.02%)	⬆️

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[jblomer]

Very nice! LGTM.