keep max TU in #define for possibility of keeping the parameter

TU max/min size are constants in the VVC draft. Reflecting this in the software.

AMVR (formely IMV) now has only one mode, which used to be mode #2
- remove SPS imv_mode parameter
- remove encoder configuration for mode #1 (mode #2 replaces mode #1)
- adapt config files to refer tp mode #1
- rename SPS syntax elements and access functions to AMVR

Note: IMV to AMVR renaming in other parts of the software should be done by proponents.

- 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.

finalize QPA code, introduce sub-CTU QPA for <=HD sequences, encapsulated in macro ENABLE_QPA_SUB_CTU

- sps_sao_enabled_flag
- sps_alf_enabled_flag
- pcm_enabled_flag
- pcm_sample_bit_depth_luma_minus1
- pcm_sample_bit_depth_chroma_minus1
- log2_min_pcm_luma_coding_block_size_minus3
- log2_diff_max_min_pcm_luma_coding_block_size
- pcm_loop_filter_disabled_flag
- sps_ref_wraparound_enabled_flag
- sps_ref_wraparound_offset
- sps_temporal_mvp_enabled_flag
- sps_sbtmvp_enabled_flag
- sps_bdof_enabled_flag

fixed encapsulation in previous commit, corrected some conditions in previous commit, replaced remaining tabs with spaces, corrected some indentations