`windows-latest` used to be that, but that's being upgrade to Windows Server 2022, which
appears to have Visual Studio Code 2022 installed.
That in turn seems to not be supported by node-gyp's version detection just yet.
So pin to the working image for now and let's upgrade later intentionally.
* Rename the package to `SixtyFPS-cpp-*` to make it easier to see that these are for C++
* Refer to the download and extraction process in the two C++ "READMEs"
* Set the home page url in the cmake project() command, from where cpack will pick it up for inclusion in the installer.
cc #631
This splits the docs and wasm workflows into shared files, that will be
called (for QA purposes) from ci.yaml as well as from nightly_snapshot
(for publishing).
The viewer build is also triggered by the snapshot workflow.
