Add an option to measure robots only

[Chardonneaur]

Hello,

Currently the log analytics script has an option to include or exclude the bot traffic with including the visitors. It would be nice to have an option in order to include bots only and not the visitors. The typical use case is when SEO practitioners just want to analyze the bot traffic.

[Findus23]

The bot detection in log analytics is really simplistic and only intended to filter out the most basic bots to reduce the amount of data sent to Matomo. So I think that this should rather be done in Matomo where the exact DeviceDetector bot detection is run.