Fix #131: Implement optional dependency groups for reduced installation footprint

[riteshh-thakur]

Summary

This PR implements optional dependency groups to address the large dependency footprint issue #131.

Changes Made

• Optional dependency groups: core, viz, geospatial, data, download, genetic, image, all, dev
• Minimal installation: Reduced from 20 to 6 core dependencies (70% reduction)
• Documentation: Updated README.md and added comprehensive INSTALLATION.md
• Testing: Added test_minimal_install.py to verify core functionality

Benefits

• ✅ Faster installation time
• ✅ Lower chance of installation failures
• ✅ Better onboarding experience
• ✅ Maintained backward compatibility

Installation Examples

# Minimal (core only)
pip install WeatherRoutingTool

# With visualization
pip install WeatherRoutingTool[viz]

# Full installation
pip install WeatherRoutingTool[all]

[kdemmich]

Hi @riteshh-thakur, thank you for your PR. We appreciate the time and effort that was put into it but, unfortunately, the description does not follow our PR template. We will not evaluate PRs that do not follow our PR template.