* Bringing citra libretro implementation over
* libretro: hook up vulkan renderer
* libretro: github actions
* libretro: gyro
* libretro: core options v2
* libretro: on ios turn off shader jit if unavailable
* moltenvk 1.3.0 introduces 8-bit indexes but allocates 16-bit for metal; this ends up allocating stream buffer * 2 = 132MiB. Instead, just use 16-bit indexes. (This will be necessary for standalone when bumping moltenvk version.)