Add clangd support for development

[LinkTed]

Add a clangd config file to the default build directory, so that clangd can find the compile_commands.json.

[LinkTed]

I also want to add a .clang-format file in another PR to set the style code. In addition to that, it would make sense to add a CI jobs, which checks the style of the code by clang format.

At least for me, it would make it a lot easier to develop on this project. If the formatting is done automatically.