Replace default gen_kw_export_name with pybind

[oyvindeide]

Drive by simplification while working on other parts of the code.

Pre review checklist

• Added appropriate labels

Adding labels helps the maintainers when writing release notes, see sections and the
corresponding labels here: https://github.com/equinor/ert/blob/main/.github/release.yml

[codecov-commenter]

Codecov Report

Merging #2719 (c99aa74) into main (09152c9) will decrease coverage by 0.01%.
The diff coverage is 16.66%.

@@            Coverage Diff             @@
##             main    #2719      +/-   ##
==========================================
- Coverage   65.34%   65.32%   -0.02%     
==========================================
  Files         651      650       -1     
  Lines       53655    53657       +2     
  Branches     4724     4724              
==========================================
- Hits        35060    35051       -9     
- Misses      17058    17070      +12     
+ Partials     1537     1536       -1     

Impacted Files	Coverage Δ
libres/lib/python/enkf_defaults.cpp	0.00% <0.00%> (ø)
libres/lib/python/init.cpp	0.00% <0.00%> (ø)
res/enkf/__init__.py	100.00% <ø> (ø)
res/fm/templating/template_render.py	84.00% <100.00%> (-0.32%)	⬇️
ert_gui/ertwidgets/validationsupport.py	79.45% <0.00%> (-19.18%)	⬇️
ert_gui/ertwidgets/__init__.py	75.00% <0.00%> (-2.28%)	⬇️
libres/lib/analysis/std_enkf.cpp	62.42% <0.00%> (-1.28%)	⬇️
libres/lib/enkf/gen_kw.cpp	59.02% <0.00%> (-0.49%)	⬇️
libres/lib/enkf/enkf_node.cpp	52.16% <0.00%> (-0.26%)	⬇️
libres/lib/res_util/block_fs.cpp	53.97% <0.00%> (+0.14%)	⬆️
... and 4 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 09152c9...c99aa74. Read the comment docs.

[ManInFez]

Since there are no issue connected to this, it would be good with a small description describing the reasoning behind this :)

[oyvindeide]

Since there are no issue connected to this, it would be good with a small description describing the reasoning behind this :)

True, I dont have that much of a reason really. I was working to alight some analysis stuff in python and c++, and came across this as a simplification.

Edit: added that to the PR text