Move from hypercall.h to libhc as a submodule

[jamcleod]

As previously discussed on slack, moves hypercall.h to its own separate repo included as a submodule. I've tested that it has built and I see no reasons the changes could successfully build while changing behavior, so no in-depth testing. Let me know if for some reason this seems incorrect.

[AndrewFasano]

Looks good to me. One last idea I'll throw out - libhc could be an installable package that we just list as a dependency - like how PANDA depends on wintrospection.

[AndrewQuijano]

Hey @jamcleod I just created a Debian Package for LibHC, and I added CI/CD

Could you please merge my PR and fix the hypercalls?

panda-re/libhc#8

But the advantage of Debian packages is that you no longer need sub-modules; just use curl to get the latest header.

I have been using the header on my fork.

    LIBHC_VERSION=$(curl -s https://api.github.com/repos/AndrewQuijano/libhc/releases/latest | jq -r .tag_name)
    LIBHC_TAG=${LIBHC_VERSION#v}
    # shellcheck disable=SC2086
    curl -LJ -o /tmp/libhc-dev_${LIBHC_TAG}_all.deb https://github.com/AndrewQuijano/libhc/releases/download/${LIBHC_VERSION}/libhc-dev_${LIBHC_TAG}_all.deb
    # shellcheck disable=SC2086
    $SUDO apt-get -y install /tmp/libhc-dev_${LIBHC_TAG}_all.deb