Add a shadow casting

[Grant-Nelson]

Add a pass which can use light positions to cast light for individual lighting depth surfaces. This will need a new technique and shader and should render from the reverse side to prevent z-fighting.

Will also need to add to the material lighting for not rendering lights based off of given depth surfaces (as texture). This work may be broken into another ticket/branch as needed.

References:

• opengl-tutorial.org
• learnopengl.com

[Grant-Nelson]

Only got it partially working in #111 for spot lights. Need to fix the depth determination and add it for other types. Also create a test for point light