When MC for luma only is desired, use existing luma/chroma parameters
instead of encoder-specific field in data structure

Also take care that luma only MC doesn't imply IBC

- The M0297 zero-out is also supported for SBT now.
- The zero-out scanning code is moved out of residual_coding_subblock.

Deleted the TU retrieval from the DQP code in xCompressCU and the TU pointer being equal to nullptr check.

Fix of the DQP signaling when there are multiple luma TUs in Single Tree and there is only one TU containing all of the chroma information

Dereferencing a nullptr should be avoided, even if the passed object is never used.
It may not be the most elegant solution to pass an empty list object, but it should work.

IBC block search history status is not reset for each frame, which may affect IBC searching results for the second frame.

- all elements of SPSNext are moved into SPS
- syntax elements of SPS are sorted according to draft (as far as possible)
- comments were added where software and draft diverge

- removes old getIBCMode functions from SPSNext
- fixes references to this function in
  * reshaper
  * hash based ME

Note: SPSNext is going to be removed. Fixes can also be applied with the removal patch.

Remove unused contexts and split intra mode contexts into luma and
chroma sets to align with text description

This reverts commit 3574c11d.

There is a conflict with JVET_M0427_INLOOP_RESHAPER that is triggering a debug assertion that checks that the width is not 1.