Before this commit, we would needlessly be building everything,
including unit tests. By only building what we need, we speed up the
process a bit and make it slightly more robust in case tests don't build
(which, coincidentally, they do not at the time of writing).
Build and publish the fsharp-language-server to a path independent from
the .NET version.
Prior to this commit, the launch script assumes that the application
will be built to a folder whose path includes netcoreapp2.0. This means
that the script will fail if you build on a machine with, say, .NET 6.
