Improve tooling scripts for contributor quality-of-life

I recently introduced npm scripts to reliably get the correct tooling necessary to compile Citybound (see CONTRIBUTING.md). There are still some things that could be improved - I will try to do so whenever I find time for it, but if anyone wants to help earlier than that, I would really appreciate it.

• Make sure that npm run ensure-tooling installs correct rust nightly, rustfmt and clippy
  • on MacOS
  • on Linux
  • on Windows
• Make sure that general tools for compiling are automatically installed on platforms that need it
  • Microsoft Build Tools 2015 for Windows (if user doesn't have them or Visual Studio yet)
  • sudo apt install build-essential for Ubuntu

What would also be nice is if in the same script there could be an opt-in to automatically install the recommended dev environment and all necessary extensions

• Ask user to download and install VSCode
• Programatically install extensions documentation on how to do that
  • The rust-lang.rust extension for code completion, formatting, go to definition etc.
  • The vadimcn.vscode-lldb extension for debugging on MacOS and Linux
  • The ms-vscode.cpptools extension for debugging on Windows
  • Debug targets should already be correctly set up in .vscode/launch.json & .vscode/tasks.json
• Make sure that after completing the setup, editing, launching and debugging Citybound works
  • on MacOS
  • on Linux
  • on Windows