x64 Emitter: Fix L bit in VEX prefix

Initial implementation ir:user

Add check before closure when emulation is running

renderer_opengl: Initalise fragment shader LUT textures

Audio Core: Skeleton

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Add support for padding vertex attributes

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.