Add only contour plot feature

[RaghavaAlajangi]

This PR aims to implement issue #210

• Implement logic
• CICD passed
• Update CHANGELOG

[codecov]

Codecov Report

❌ Patch coverage is 10.00000% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.31%. Comparing base (f227e20) to head (78060ef).

Files with missing lines	Patch %	Lines
dcscope/gui/pipeline_plot.py	0.00%	7 Missing ⚠️
dcscope/pipeline/core.py	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #222      +/-   ##
==========================================
- Coverage   78.39%   78.31%   -0.09%     
==========================================
  Files          67       67              
  Lines        7671     7681      +10     
==========================================
+ Hits         6014     6015       +1     
- Misses       1657     1666       +9     

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[RaghavaAlajangi]

Hi Paul,
Do we need a test function here?

[paulmueller]

Hi Paul, Do we need a test function here?

Yes, please add two tests:

• load two datasets and create a zoomed-in contour plot
• load a dataset and create a contour plot with contour levels that don't make sense (e.g. at 100% of KDE)