Create .clang-format file in lb-project-init and lb-dev

lb-project-init (as for the other generated files) use a hardcoded template for the new file if not already present. The template is a copy of .clang-format from Gaudi/v30r3.

Since a change in .clang-format may be very disruptive, projects should have it committed in the repository, the one provided by LbScripts is just a default.

OTOH lb-dev copies the .clang-format file from the upstream project, so that changes will have consistent formatting in case of a change of the default. If the upstream project does not have the style file, lb-dev uses the LbScripts default.

We may extend this MR to use @sponce Git pre-commit hook for automatic checking of the code style.