Add full support for Homebrew dependencies

[csparker247]

The Homebrew-provided vtk now links against Qt6, which means we can now use Homebrew to provide all external dependencies:

# get source
git clone https://github.com/educelab/volume-cartographer.git
cd volume-cartographer

# install dependencies
brew bundle

# configure and build the project
cmake -S . -B build
cmake --build build

Changes

• Add Brewfile with project dependencies
• Add Homebrew-based macOS test builds on GitHub hosted runners
• By default build ACVD in source