Code was salvaged from !306

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

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

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

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

 - CE9.2.1g + RefinedMV only for MC and TMVP + SAD cost