Disable mysql bin log by default

Turns out bin log can quickly fill up your disk space. Also, the [primary uses of binary log](https://dev.mysql.com/doc/refman/8.0/en/binary-log.html) are:
```
* For replication, the binary log on a master replication server provides a record of the data changes to be sent to slave servers...
* Certain data recovery operations require the use of the binary log...
```

In case someone might want bin log for 2nd use case, he/she can enable it manually. It's best to disable this feature as most of the time it won't be necessary(AFAIK).