Provide a Dockerfile

[merkrafter]

Could you provide a minimal Dockerfile for how to compile the tests, please? I tried gcc and clang, and make and ninja in all possible combinations and none of them worked out of the box (I know gcc is not officially supported, but it would be nice to work anyway). clang only works for me if I remove the -stdlib option that is added automatically by the build systems. Eventually, I would like to use bounded::integers in a cmake project that is build by a CI pipeline.