The option was declared in Application::getDefaultInputDefinition but
never consumed, so a user passing --log foo.log saw the option in --help
yet no file was ever written (see phpDocumentor#1872).

Wire a LogConfigurator event listener that, on ConsoleEvents::COMMAND,
pushes a Monolog StreamHandler for the requested path. The handler
level follows the console verbosity (notice, -v info, -vv/-vvv debug)
and --quiet disables file logging entirely, matching the intent
captured in Transform.php. Paths are canonicalised through Monolog
Utils so a relative and an absolute form dedup to the same handler on
nested ConsoleEvents::COMMAND dispatches, and the same dedup is applied
to the ConsoleLogHandler to avoid duplicate console output.

Covered by new unit tests for missing / empty / quiet cases, the
verbosity-to-level mapping, the nested-dispatch and relative-path
dedups, and distinct log files producing two handlers. A functional
test runs phpdoc with --log and asserts the target receives a stable
log line.

Fixes phpDocumentor#1872