This release introduces some new features, alongside a bunch of miscellaneous
bug fixes across the board, in particular, major improvements to the Vulkan
renderer.

Additions:
- add pl_gpu_limits.host_ptr_slow to notify if host pointer import is slow
- add PL_DEINTERLACE_BWDIF
- add PL_CLEAR_BLUR and pl_render_params.blur_radius to allow clearing with a
  blurred copy of image
- add pl_daylight_from_temp, pl_blackbody_from_temp
- add PL_COLOR_SYSTEM_YCGCO_{RE,RO}
- add pl_vulkan_swapchain_params.{alpha,color}_bits
- add pl_d3d11_swapchain_params.{alpha,color}_bits

Changes:
- pl_shader_{encode,decode}_color no longer (de)linearizes XYZ
- pl_avframe_set_repr now sets frame.alpha_mode
- pl_white_from_temp now computes a blend of the daylight and blackbody
  temperatures (old behavior can be achieved with pl_daylight_from_temp)

Fixes and enhancements:
- fix double application of alpha mode
- fix math in pl_primaries_compatible
- refactor and fix host-visible VRAM limit for Vulkan
- fix unsigned integer overflow with complex overlays
- fix many issues with frame_queue, mostly for interlaced sources and other
  esoteric files
- fix internal primaries/transfer function mapping of Vulkan color spaces
- Vulkan swapchain improvements by using VK_KHR_swapchain_maintenance1 when
  available
- switch to extended HLG gamma formula
- fix issues with SDR output in HDR mode on Windows with d3d11
- fix pl_filter_config_eq when comparing tunable with not tunable
- improve surface format and colorspace selection for Vulkan swapchains
- use deferred memory allocation for Vulkan swapchains
- render overlays with the same colorspace as source image
- convert background color to target and use infinite contrast for them
- prefer Vulkan formats that can be used for direct-to-display output on Apple