Avoid duplicating variables and functions for each reference list

Changes include:
- use [[maybe_unused]] instead of cast to (void)
- use generic lambda function and remove related comment about C++11
- update MSVC version check
- don't condition '#pragma once' on MSVC version

subsumed setMIPFlagISPPass into setBestPredModeDCT2 and removed getBestPredModeDCT2 (because it was unused)

- remove picture header allocations at the encoder
- use correct boundary location in reference pictures after removal of new PH

Should also fix memory allocation issues with PicHeader.

(m_layerId instead of layerIdx)

Macro: JVET_AB0070_POST_FILTER_HINT