Add everest gradient plots

[yngve-sk]

Approach:

[codecov-commenter]

Codecov Report

❌ Patch coverage is 34.88372% with 112 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.20%. Comparing base (6b61bdd) to head (cbf0c56).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...ools/plot/plottery/plots/everest_gradients_plot.py	13.11%	53 Missing ⚠️
src/ert/dark_storage/endpoints/responses.py	9.37%	29 Missing ⚠️
src/ert/gui/tools/plot/plot_window.py	66.66%	12 Missing ⚠️
...s/plot/widgets/everest_control_selection_widget.py	68.75%	10 Missing ⚠️
src/ert/gui/tools/plot/plot_api.py	11.11%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #12892      +/-   ##
==========================================
- Coverage   90.52%   90.20%   -0.32%     
==========================================
  Files         443      445       +2     
  Lines       30595    30763     +168     
==========================================
+ Hits        27697    27751      +54     
- Misses       2898     3012     +114     

Flag	Coverage Δ
cli-tests	36.89% <0.00%> (-0.23%)	⬇️
gui-tests	67.49% <33.13%> (-0.22%)	⬇️
performance-and-unit-tests	76.78% <34.88%> (-0.25%)	⬇️
test	46.13% <15.11%> (-0.15%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[codspeed-hq]

Merging this PR will improve performance by 81.96%

⚡ 1 improved benchmark
✅ 33 untouched benchmarks

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
⚡	test_direct_dark_performance[gen_x: 20, sum_x: 20 reals: 10-gen_data_with_obs-get_record_parquet]	40 ms	22 ms	+81.96%

---

_{Comparing yngve-sk:26.02.add-ever-gradient-plots (cbf0c56) with main (f3122f2)}

[berland]

I added #12934 on which you can cherry-pick rebase.

The data_for_gradient should probably also be wrapped in the context manager for consistency with get_response

[berland]

(an alternative to using threads could be to supply a list of ensemble id's here - changing the api as needed)

[berland]

No, probably not a very good idea.

[andreas-el]

I take it that accept are acceptable media types? Not very intuitive argument perhaps?

[yngve-sk]

Yep, suggest leaving rename / maybe a small refactor for separate issue/PR though, this is also in parameters.py

[berland]

I think this can be made nice with a match construct.

[berland]

Let's go!