Show "caretaker label" as circle to each tree node (on map)

[julizet]

Background: Why this issue?

• second step of Issue #183

Deliverables: How to fix the issue?

• add another circle (green outline?) to tree nodes which are nurtured by Berlin authorities to the frontend
• to avoid performance issues: show caretaker circle not before a specific zoom level
• add the "caretaker labeled" trees to the filter of adopted trees OR create a very own filter for "caretaker labeled trees"

Output: Gain of fixing the issue?

• if authorities are taking care or not should be visible on map (without clicking at a specific tree)

Issue creation checklist

• I have attached one of the priority labels HIGH, MIDDLE, LOW
• I have attached other labels with regard to the issues purpose (i.e.enhancement, bug, community feedback)