Implement CrawlerLogger, a logger that controls every logging related to the crawler

[peterbencze]

Logging should be toggleable in the configuration by setting debug mode to true. This makes the crawler to print debug messages to the console. By specifying an optional argument (logFilePath), this output should also be written to the specified file.
If debug mode is set to false, no output should appear in the console.

Example:
config.setDebugMode(true);
config.setDebugMode(true, "/path/to/file");