Add Highway CRC implementation

Description

This MR adds a Highway ported implementation of the armral CRC function set. The merge includes the following changes:

1. Added a Google Highway submodule
2. Updated the build process to compile Google Highway, when selected
3. Split the acle and highway build targets using custom cmake files: armral_acle.cmake.in and armral_hwy.cmake.in
4. Added a Highway implementation for the functions in crc_common.hpp, this was done by moving the acle implementation to its own subfolder and adding the Highway implementation to a highway subdirectory. A common crc_common.hpp selects the appropriate implementation.
5. Added a hwy_types.hpp header file.
6. Benchmarks and unit-tests have been added.

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.