Feature: Adapt class

[Davknapp]

Closes #2046

This is a draft PR for an outline (and hopefully later on meant seriously) adapt class.

It provides a class that manages the adaptation of a forest. The adaption is split into several parts:

• the gathering of the adaptation action via element-callbacks
• the family check
• the execution of the action matching the results of the element-callbacks and the are_family checks.

The goal is to provide a general functionality of adaptivy whilst also providing the flexibilty to speciallize for other adaptions, like forests with wholes, or subelements. The steps can be overwritten to provide such functionality and also to create new adaptions workflows more easily.

Please feel free to discuss it in this draft PR.

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[codecov]

Codecov Report

❌ Patch coverage is 0% with 19 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.87%. Comparing base (411b90b) to head (4574fc7).
⚠️ Report is 96 commits behind head on main.

Files with missing lines	Patch %	Lines
...orest/t8_forest_adapt/t8_forest_standard_adapt.hxx	0.00%	19 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2045      +/-   ##
==========================================
- Coverage   77.95%   77.87%   -0.09%     
==========================================
  Files         113      114       +1     
  Lines       19087    19108      +21     
==========================================
+ Hits        14880    14881       +1     
- Misses       4207     4227      +20     

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