Increase time precision for logs in debug
Increase time precision for logs in debug

When the stack is started with --log-level=debug, the format for the
time in the log message will include the nano-seconds. It will help for
merging several log files from several stacks when debugging the
integration tests for sharing.

nono/cozy-stack,nono/cozy-stack,nono/cozy-stack,nono/cozy-stack,nono/cozy-stack