Signalling of CPB timing parameters for sub-layers in DU-based HRD
operations
Remove pt_max_sub_layers_minus1 and use corresponding syntax element in
BP SEI
Make parsing of BP, PT and DUI SEI independent from SPS

 - Signal a single bit depth to be used for both luma and chroma.
 - Use u(4) for SPS IDs in the SPS syntax as well as in other places for referring to SPS.
 - Code chroma_format_idc with u(2).
 - Code log2_max_pic_order_cnt_lsb_minus4 with u(4).
 - Specify the value range of min_qp_prime_ts_minus4 to be 0 to 48, inclusive.
 - Specify the value range of log2_min_luma_coding_block_size_minus2 to be 0 to log2_ctu_size_minus5 + 3, inclusive.

 Implementation of the Dependent RAP indication SEI message. Pictures are marked as DRAP pictures using the encoder config parameter DRAPPeriod, which sets DRAP pictures periodically. Conformance checks are performed at the decoder side to verify that the DRAP pictures follow the constraints in the VVC specification.

removes the last remains of HEVC related code

- create own files for HRD classes
- rename HRD to HRDParameters
- create HRD class that can hold all HRD related parameters as base for encoder/decoder specific implementations

- tiles are in the VVC spec for 3 meeting cycles now
- cleanup helps with adaptation for tiles to current draft