Support for bazel build system

[bauerm97]

Hey @offa , I work for a company that is considering taking a dependency on this project for use. We are using the bazel build system. If we decide to use this library, would you be willing to accept a contribution from us to add support for using bazel in addition to cmake?

[offa]

Thanks for your suggestion. I do not have any experience or use case with Bazel, thus I can't really maintain it. However, if someone is willing to provide a working integration (and maybe some maintenance here and there) I guess it's a good addition. 👍

But it must be clear that CMake is the main build system and bazel support is some kind of experimental or semi-official (respectively, at least depending on helping hands :-) ).