Add CMake setup

[r-ash]

This is really quite a mess and I'm a bit skeptical of the value added at this point. This was built with https://github.com/friendlyanon/cmake-init

clang-tidy is causing a lot of pain and not really that much tidying up we need to do. To get this ready still remaining TODO is

1. Support generating the new target (which has no clang-tidy warnings) I have pushed this for now into generated_new_target
2. Review all the changes it has made
3. Get CI working (has broken the python builds which use this)
4. Get R working, I have installed "array" as a system library to avoid raising warnings and analysing it with clang-tidy. But that is now causing problems for R with how we link to it.

I'm wondering if this just doing too much really for a first pass. Perhaps we should try add a very simple CMake setup which compiled the header only code, and runs the standalone .cpp file with ctest and leave it at that for now? We can add clang-tidy later