WebDriver-based harvester for groundwater PoM in Thüringen.

Fittingly, this is part of user story 666.

To test this, one needs to install Xvfb and Chromium in the development VM, i.e. run

> sudo apt install xvfb
> sudo snap install chromium

and run ChromeDriver in a separate terminal, i.e. invoke

> xvfb-run chromium.chromedriver

This will need companion MR in

• entwicklung so prerequisites are installed automatically
• testbetrieb so ChromeDriver is available as a system service when the harvester needs it