Feature request: Add ability to copy & paste custom objects

[james-h-dt]

Could work like: Select an existing object, RMB shows new context menu. RMB > Copy, then single click target loctation, RMB > Paste.

Thought a scenario might help explain this suggestion: I'm annotating a standard map with some additional intelligence. For example, river crossing points or lakes which cannot be crossed. I'm using a small green circle to mark up my first crossing point. I'd like to re-use the same circle (size, colour) to mark other crossing points. At the moment, I need to recreate the same circle. Would be much quicker and neater to copy & paste the same circle.

Stretch feature: Have a reusable library panel, where objects could be tagged as assets. Assets would then appear in the panel and could be drag-and-dropped into the map.