This commit:
* Adds a new subproject, audio_core.
* Defines structures that exist in DSP shared memory.
* Hooks up various other parts of the emulator into audio core.

This sets the foundation for a later HLE DSP implementation.

BitField: Make trivially copyable and remove assignment operator.

Fragment lighting support in the HW renderer

- Also implement D0 LUT enable.

- No functional difference.

- Gets us LUT interpolation for free.
- Some older Intel GPU drivers did not support the big UBOs needed to store the LUTs.

- Diffuse
- Distance attenuation
- float16/float20 types
- Vertex Shader 'view' output

hwrasterizer: Use proper cached framebuffer addr/size

backend: defaulted move constructor/assignment