Integrate AMD FSR1 (v0.6.6)

[codeonwort]

This PR integrates AMD FSR1 (v1.0.2).

1. Add cvar r.super_res.method to toggle FSR1.
2. Add cvar r.fsr1.quality to control FSR1 quality mode. (0~3: ultra quality, quality, balanced, performance)
3. Add cvar r.fsr1.sharpness to control FSR1 sharpness. (0.0~2.0, default is 0.2)

NOTE: Always use FP32 fallback for now. I used GTX 1660 Super for this work but it does not support GLSL FP16 extension. I'll test FP16 when my RTX 3080 Ti is available. Also, need to check Ryzen 6800U.

[codeonwort]

FP16 version is neither available on Ryzen 6800U. Following two extensions are required, but not supported:

• GL_EXT_shader_16bit_storage
• GL_EXT_shader_explicit_arithmetic_types

Do merge in current state as my RTX 3080 Ti is not available now. Check it later.

[codeonwort]

These GLSL extensions are also unavailable in RTX 3080 Ti.

• GL_EXT_shader_16bit_storage
• GL_EXT_shader_explicit_arithmetic_types

In OpenGL, it seems I have to use GL_NV_gpu_shader5 instead of GL_EXT_shader_16bit_storage, and define explicit conversion functions as there is no alternative to GL_EXT_shader_explicit_arithmetic_types.

[codeonwort]

FP16 mode is available by 79fe014, anyway the GPU cost is not that different.