vkencoder-private: simple non-abi enhancements
- vkencoder-private: keep only one DPB view for layered DPB
- vkencoder-private: increase reference slots array
- vkencoder_private: move view creation to picture init
- vkencoder-private: shuffle up operation and query creation
- vkencoder-private: shuffle up get format to bail out better
- vkencoder-private: define encoded feedback flags by removing override bit
- vkencoder-private: fix parameters overrides