Feature: Ancestor search

[holke]

Closes #1715

Describe your changes here:

Currently waiting for #1640 to merge.
Will add a description afterwards.

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General

• The reviewer executed the new code features at least once and checked the results manually.
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[codecov]

Codecov Report

❌ Patch coverage is 45.45455% with 36 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.44%. Comparing base (d4a8b44) to head (331cc9b).
⚠️ Report is 47 commits behind head on main.

Files with missing lines	Patch %	Lines
src/t8_forest/t8_forest_private.cxx	0.00%	36 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1714      +/-   ##
==========================================
+ Coverage   77.41%   77.44%   +0.03%     
==========================================
  Files         113      113              
  Lines       19178    19095      -83     
==========================================
- Hits        14847    14789      -58     
+ Misses       4331     4306      -25     

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[Davknapp]

A first round of remarks! Thanks for this addition!

[holke]

Tests are passing now. Only a minor change was required (removing constexpr).

[Davknapp]

In general it looks good, but Codecov tells me, that the functions in t8_forest_private.cxx are not covered. I am ok with merging, if we start to develop a test on another branch.

[holke]

I will have a look at it and decide if we merge now or if i could develop a test quickly.

[holke]

@Davknapp let us merge it here and i will develop a test on a new branch soon.

See also #2111 and #2113

[Davknapp]

CodeCov won't let us merge until the patch does not decrease the overall coverage by more than 0.2%

[holke]

Alright, will do the tests here then :)