Improve visual studio searching algorithm + add a config option
commit d685e3f7:
cerbero: Allow specifying a custom location for Visual Studio
Sometimes Visual Studio is installed into a custom location, or the
user wants to specifically select a particular Visual Studio
installation when there are many installed.
You can set the `vs_install_path` and `vs_install_version` config
variables to override the automatic detection of the Visual Studio
installation location. F.ex., in `~/.cerbero/cerbero.cbc`
This is needed for running Cerbero on the Windows CI, where we use
Visual Studio Build Tools 2019 installed in `C:\BuildTools`.
commit c36ed745:
cerbero: Prefer searching using vswhere if available
vswhere.exe is the preferred way of detecting Visual Studio
installations if it is available. We still fallback to searching the
default installation locations if it is not available.