Include log writes as db writes

Log table writes are not counted as db writes, the benefits of this are:
* It is easier to detect any regression in dbwrites (one of the most important factors) as a difference will be that big that will always be outside the confidence interval (the defined threshold)
* A new log entry into the database is not a regression, is like adding a new feature.

On the other hand:
* Being strict, a log write is a db log and we should count them as we count any db write

I'm adding a new setting to manage this. 

Once we release 2.6 and the next minor 2.5 we must update the base commits as with this kind of changes previous runs will not be comparable.