Update screenshots in toy tutorial

[Flix6x]

The three UI screenshots in the toy tutorial could use an update, and two new ones could be added.

Updates:

• The asset page has had a make-over, with the map hidden in a side panel. The map is still mentioned in a note on the tutorial, so I'm not sure right now whether the screenshot should still show the contents of the sidepanel, or it would just be a distraction from what the tutorial is really about: scheduling.
• The other two UI screenshots show the sensor page for different sensors. These pages have also had a make-over, so it would be good to update them.

New ones:

• Just before the section on taking into account solar production, to round off the previous section which ran through the tutorial without taking into account solar production, we can show the asset page again. It should now show the previous graphs (prices and the schedule) in one view.
• At the end of the tutorial, we should show how the resulting schedule looks different when we have taken into account solar, with a new screenshot of either the sensor page (of the battery sensor), or of the asset page.

Note that we store relevant screenshots in a different repo.

Hint: Firefox has a nice feature to screenshot the whole page.