[src] Add a helper script to execute codespell locally

The script extracts and runs the codespell call and parameters from .gitlab-ci.yml. This is helpful in order to run codespell locally while respecting the (ingnore) list defined in the CI file without having to copy and paste this manually. Since the script detect the module source directory from its own location, it can be called from any working directory, especially from subdirectories of the source directory.