v3dv: Move extension tables & ICD json to C
Slightly after Jason's work to add a common dispatch framework (!8676 (merged)) he did some extra cleanups and extra utilities at vk util to be able to move the extension tables and ICD from python scripts to C (!8792 (merged)). radv did the same shortly after that (!8900 (merged)). Among other advantages, it avoids the need to keep maintaining two python scripts (so with this MR, now v3dv has no custom python script). A more detailed explanation of why that makes sense can be found on Jason's !8792 (merged).