Remove built-in render pipeline support

[elfin8er]

I am trying to test a table using Unity's built-in render pipeline, but balls don't seem to be working currently. According to the documentation: "the built-in renderer is legacy not recommended", but I see no mention if it not being supported.

Unity version: 2022.3.6f1

Steps to reproduce:

• Create a new Unity project with the 3D template
• Install VPE packages:
  • org.visualpinball.engine.unity
  • org.visualpinball.unity.assetlibrary
  • org.visualpinball.engine.pinmame
• Save a default .vpx table from VPX
• Import .vpx into VPE using Visual Pinball > Editor > Import Wizard
• Enter Play mode
• Pressing/holding Enter doesn't launch a ball

[arthurkehrwald]

I don't think it makes sense to support it. The built-in render pipeline is slowly being phased out and supporting three different render pipelines is just a maintenance nightmare. I can't think of any benefits for users either.

[freezy]

Yes, I think we'll remove support for the built-in renderer.

I think the path forward is to focus on HDRP and when Unity merges the pipelines in v7, we'll adapt accordingly.