Add shell script for installing dependencies

[ngernest]

I recently set up this repo on a new machine and went through the process to manually install dependencies for local development.

To automate / document this process, I decided to create a script install.sh, in case we also need to install this repo again on a server (Gorgonzola / Havarti) in the future.

The script installs the following (via Homebrew on MacOS or apt-get on Linux):

• uv (for Python dependencies)
• just (to use Justfiles)
• Install's Nikil's fork of Runt via cargo install --git https://github.com/Nikil-Shyamsunder/runt.git (as described in Migrate to Runt #252)
• Installs Yosys
  • Note: this does brew install yosys, so it may end up installing a different version from Yosys from what is done in CI (CI runs the entire setup-oss-cad-suite, which takes much longer) -- hopefully doing brew install yosys is sufficient for this script
• Runs uv sync to set up Python virtual env

I checked this script using the shellcheck tool and ran it locally on my machine to check the script works.