Logging changes in bot.py

- Adds a debug.log with level=DEBUG.
- Changes the time format in the log files to [%Y-%m-%d][%H:%M:%S]
- Adds a [%H:%M:%S] time prefix to console output.
- Makes bot only create connections after all plugins are loaded. This is to ensure that all plugins using server output (for example: log.py) are loaded before server connection begins.
- Makes the logging level for console INFO instead of DEBUG. This makes debug.log the only file with level=DEBUG

Let me know what you think of these changes. This output looks nicer to me, it's not necessarily better though.