Reduced shader program state changes & property uploads

[adriengivry]

Description

Supersedes #811.

This PR aims to reduce shader program state changes & property uploads by:

• Re-ordering opaque pass draw calls by material key
• Reducing unnecessary shader program changes by keeping track of the last used program
• Keeping track of property changes, to efficiently skip uploads if the data didn't change
• Re-writing the GetVariant method
• Added a defaultValue to MaterialProperty instead of calling the expensive UniformToPropertyValue every time a single use property need to be reset

Related Issue(s)

Fixes #445

Review Guidance

Write here.

Screenshots/GIFs

DrawFrame (Cargo)

• RTX 2080 ti
• Ryzen 9 3900X
• 1920x1080p editor, default layout

Went from ~7.79ms to 3.78ms.

Before	After

DrawEntity

Went from expensive draws...

to one initial draw, and cheap subsequent draws, thanks to property caching.

AI Usage Disclosure

None

Checklist

• My code follows the project's code style guidelines
• When applicable, I have commented my code, particularly in hard-to-understand areas
• When applicable, I have updated the documentation accordingly
• My changes don't generate new warnings or errors
• I have reviewed and take responsibility for all code in this PR (including any AI-assisted contributions)