Docs: indicate where to find an excellent tutorial on using CMake #8475
Motivation / Problem
As mentioned in #8465, we only mention how to produce a Debug build. We kinda assume people know CMake when starting to develop. This does not have to be the case.
Instead of explaining all the ins and outs of basic CMake usage, reference their excellent tutorial which helps you through the basics in a few lines of text.
Checklist for review
Some things are not automated, and forgotten often. This list is a reminder for the reviewers.