ci: Add windows-ci-shared that uses vcpkg.

[waywardmonkeys]

This uses vcpkg to install a copy of Harfbuzz rather than using the bundled feature.

[mrobinson]

It seems quite likely that you will need to use the vcpkg crate to set up the build in build.rs the same way that the harfbuzz-bindings crate does.

[waywardmonkeys]

Yes ... but then when digging into that, I found a whole bunch of other things that are wrong.

For this one, for example, the vcpkg package doesn't specifically enable directwrite on Windows, but we assume that it is available on Windows.

I've got some local branches where I start messing with default features, but I'm not excited about any of the approaches to changing it yet.

[waywardmonkeys]

Got a fix landed in vcpkg to allow not building with free type. Will add a direct write feature soon.