Adds custom saturation range widget

[leoyala]

Description

Adds custom double spin box widget to control saturation min and max values to display saturation colored mask in viewer.

Summary of other changes:

• Adds @brief specifier to documentation.
• Fixes tests based on new saturation range implementation.

Related Issue

#39 #60

Type of Change

• 📚 Examples / docs / tutorials / dependencies update
• 🔧 Bug fix (non-breaking change which fixes an issue)
• 🥂 Improvement (non-breaking change which improves an existing feature)
• 🚀 New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to change)
• 🔐 Security fix

Checklist

• I've read the CODE_OF_CONDUCT.md document.
• I've updated the code style using the pre-commit hooks.
• I've written tests for all new methods and classes that I created.
• I've written the docstring for all the methods and classes that I used.