Hide PropertyValue, IPropertyValue, and IReference types from the `windows_foundation` library

[halildurmus]

Description

Hides PropertyValue, IPropertyValue, and IReference types from the windows_foundation library. They are exposed through the internal library instead.

Also contains small tweaks to the projection classes.

Related Issue

None

Type of Change

• [ ] ✨ New feature (non-breaking change which adds functionality)
• [ ] 🛠️ Bug fix (non-breaking change which fixes an issue)
• [ ] ❌ Breaking change (fix or feature that would cause existing functionality to change)
• [x] 🧹 Code refactor
• [ ] ✅ Build configuration change
• [ ] 📝 Documentation
• [ ] 🗑️ Chore