Hqc update reference implementation

[vsoftco]

Updates HQC to https://gitlab.com/pqc-hqc/hqc v5.0.0. Minimal changes in the upstream code.

[dstebila]

Hi @vsoftco, I've tried to fix the code formatting CI failures by applying astyle following the instructions at https://github.com/open-quantum-safe/liboqs/blob/main/CONTRIBUTING.md#coding-style

[xuganyu96]

Hi @vsoftco, this is unfortunately not adequate for updating liboqs's HQC implementation. These code changes will not build, and CI pipeline did not report failure only because HQC was disabled by default.

I understand that the lack of liboqs's documentation is making integrating additional implementation confusing. We are working on better docs and revamping upstream integration process. If you are still interested in contributing, feel free to raise an issue, and we can walk you through the process.

I will close this pull request for now.

cc: @dstebila

[dstebila]

I'd like to keep this open since it is a target feature of liboqs 0.16.0.