Add auto option for existing_network_spacing

[mszell]

Description

Add auto option for existing_network_spacing

Related Issue

Fixes #179

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to change)
• 📝 Documentation update
• 🧹 Code refactor (no functional changes)
• ✅ Test update

How Has This Been Tested?

pytest

• Unit tests
• Integration tests
• Manual testing

Test configuration:

• OS:

Screenshots (if applicable)

Checklist

all applicable

• My code follows the project's style guidelines
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation
• My changes generate no new warnings
• I have added tests that prove my fix/feature works
• New and existing tests pass locally

Additional Notes