Customize the process title of the worker's child processes

[kureuil]

Celery can use the setproctitle package to rename a child process, making it easier to identify the task being executed by a worker child process when visualizing them in ps or top for example.

setproctitle is based on code written by the PostgreSQL project: https://doxygen.postgresql.org/ps__status_8c_source.html

It could be interesting to port this code to Rust and integrate its functionality to batch.