Updates CMake files to account for arm64 architecture.
Consider __ARM_NEON to detect ARM architecture in C++ code.

Fix SPS crash for RGB content

See merge request !2709

- includes minor fix for software manual

Cleanup: replace TAB characters with spaces in config files

See merge request jvet/VVCSoftware_VTM!2708

JVET-AF0310: Processing Order Nesting SEI message

See merge request jvet/VVCSoftware_VTM!2705

Fix debug bitstream for multilayer

See merge request !2702

JVET-AF0122-SW: Lagrange multiplier optimization for ALF

See merge request !2700

Fix #1621: Compilation issue in non-X86 environments

See merge request !2706

Fix #1622: Initialising NNPFC SEI attributes in the default constructor

See merge request !2707

Remove toLast and unused variables in ClpRngs

See merge request jvet/VVCSoftware_VTM!2704

Remove parameter UseBLambdaForNonKeyLowDelayPictures

See merge request !2703

Fix out-of-bounds access in EncCu::updateRdCheckingNum

See merge request !2699

The value of this parameter is never used

Fix debugBitstream functionality

See merge request !2701

# Conflicts:
#   cfg/encoder_lowdelay_P_vtm.cfg
#   cfg/encoder_lowdelay_vtm.cfg
#   source/Lib/CommonLib/TypeDef.h