core: fix and renamed getLocalPath -> get_local_path: - renaming is following global methods renaming to use snake_case - for reasons lost in the mists of time, a `profile` argument was used while checking if `client` is set is enough, and `client.profile` was escaped but actually not used in the path.

this certificates are used to enable TLS during tests. Those must be the same as in
backend_e2e (they are generated there)