Implement ColorDepthEffect

[vanruesc]

Description

Implement a ColorDepthEffect.

Tasks

• Create ColorDepthEffect.
• Create color-depth demo.
• Add unit test.

Implementation Details

• The implementation from v6 can be copied mostly as-is.

[benjamin-white]

Hello, I'd like to take a look at this one if that's ok please?

[vanruesc]

Sure, have fun 👍

[benjamin-white]

Great thanks @vanruesc

I have opened a PR here: #604 If it's generally the right shape let me know, if not, no worries :)