Wrap lifecycle hooks and other operations in `start`/`stop` log messages

Recently Codespaces has gotten several reports where the root cause was difficult to debug. It would be useful if the logs emitted from the CLI clearly mark the start and end of a lifecycle script - perhaps like the following:

```
--- starting to execute 'postCreateCommand' script 'foo'

... foo output...

--- 'postCreateCommand' script 'foo' exited code 0
```

This would be particularly helpful in cases where `foo` does not emit any logs.

Start by tracing where the CLI executes lifecycle scripts and where it currently emits related logs. Define the start and completion messages for scripts such as postCreateCommand, including the command name and exit code, then verify that silent scripts are clearly bounded in the CLI output.

Scritto dal modello di indicizzazione a partire dal testo della issue.