An SDK starter template & guide

This great SDK is exactly what I was imagining of when I saw the (_reasonably_) cumbersome C API in the OpenCL guide. However, it is still a little confusing for a new user to figure out where to start. Should I:
1. use this whole repo as another dependency, or should I
2. tailor it to be a codebase as my own repo?

Even the draft guide I found in the issue #3 did not utilize the SDK utility. For now I am pursing the second way.

I learnt some CMake but using it still heavily relies on Google. The `add_sample` macro is great but only for the samples. This repo provides splendid examples with an elegant project structure, but if it can include a boilerplate to start with, that would be even better. Also, a practical "Get Start With" guide will bring in much more usefulness.

Thank you for your work. It is really appreciated. Personally, I am especially interested in the GL&CL interop part, which attracted me here.

Start by reviewing the repository's existing samples, the add_sample macro, and the draft guide referenced in issue #3. Define whether the starter should be consumed as a dependency or copied into a new repository, then scope a boilerplate and practical getting-started guide. Done means a newcomer can choose an approach and begin a project without relying heavily on external searches.

Written by the indexing model from the issue text.