cmake-init + Conan

This is an example repository showcasing Conan integration with cmake-init generated projects.

The list of changes to make when integrating with Conan:

• Add a conanfile that lists the dependencies and the generators to use
• Add a conan preset to CMakePresets.json, which uses the toolchain generated by the CMakeToolchain generator that enables CMake to find config files generated by the CMakeDeps generator
• Inherit from the above preset in your CI and dev presets
• Mention in HACKING.md that the project uses Conan
• Mention in BUILDING.md what the dependencies are of the project and that acquiring them via Conan is an option
• Install Conan in the CI workflow and the dependencies

Every other change in the repository was made just to make this repository more focused on showing how to integrate with Conan, like removing unused presets and trimming the CI workflow yaml.