radv: use vk_pipeline_cache

radv: use vk_pipeline_cache

Replaces the RADV pipeline cache with an implementation
based on the common vk_pipeline_cache.

We use a dual-layer approach with two types of cache entries.

  1. radv_shader:
    - serialized as radv_shader_binary
    - uses SHA1 of the binary as key
  2. radv_pipeline_cache_object:
    - contains pointers to associated radv_shaders
    - serialized as list of SHA1
    - uses the pipeline hash as key

In combination with single-file disk-cache, this reduces the cache size by ~60%.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22030>