Port Updated LDPC to Highway

Description

This merge request contains google highway port of the updated LDPC code .

Checklist

• [] Contribution meets RAL's licence terms
• [] New functions adhere to RAL's naming scheme
• [] Contribution conforms to RAL's directory structure
• [] Documentation updated
• [] "Unreleased" section of the Changelog updated
• [] clang-format and clang-tidy run and changes included (C/C++ code)
• [] flake8 run and changes included (Python code)
• [] cmake-format run and changes included (CMake code)
• [] Tests added or updated
• [] Tests pass when run with AddressSanitizer
• [] Benchmarks added or updated

For any items that are not checked, please provide details.