Use godotenv

This allows the process to use the ``.env`` file without any extra user steps needed. 

The configuration in use is logged so it is clear what the expected environment vars will be:

```
16:55:21 bot.1      | 2014/07/10 16:55:21 START. Use 'botbot -help' for command line options.
16:55:21 bot.1      | 2014/07/10 16:55:21 Environment variables have been set from the .env file
16:55:21 bot.1      | 2014/07/10 16:55:21 STORAGE_URL:  postgres://localhost:5432/botbot
16:55:21 bot.1      | 2014/07/10 16:55:21 REDIS_PLUGIN_QUEUE_URL:  redis://localhost:6379/0
```