This prompts users opening the workspace (on a new device) for the first
time to install the lean extension
# Summary
Link to `RFC` or `bug` issue: N/A
This sets the build directory to `build/release` for the "CMake Tools
for Visual Studio Code" extension documented at
https://vector-of-bool.github.io/docs/vscode-cmake-tools/settings.html#cmake-builddirectory.
It also sets the generator to `make`, since otherwise it tries `Ninja`
which doesn't work.
Without these settings, the extension runs configure in a bad place at
startup.
This does *not* add the cmake tools extension to the default workspace
configuration; the goal is simply to prevent bad behavior for users who
already have the extension enabled.
# Summary
Screenshot of this in action:

Link to `RFC` or `bug` issue: N/A, this is not a bug nor a user-visible
feature.