Add Copy operation to the radial menu

[bhousel]

Now that we can Copy and Paste with ⌘-C and ⌘-V (see #2498), it would be nice to add a Copy operation to the radial menu for discoverability.

@samanpwbb, can you work your magic to make a copy icon?

Not sure whether or not a "Paste" button makes sense here too.

[pmailkeey]

I take this as a different 'copy'. Using keys to copy can utilise the clipboard. Copying using the annular menu ought to work differently - i.e. as per the move function that leaves the original in place. That way, a paste function would not be needed.

I've slept since then - lines - click the last point and one gets an option to extend the line. How about using that '+' symbol to add another area or line if that is what is selected when the symbol is clicked on and stop adding extra ones when the same place is clicked on twice - just like adding more points to a line ?

[quincylvania]

Not sure whether or not a "Paste" button makes sense here too.

I think it'd be frustrating to have copy without paste. This does mean we'd have to enable right-clicking on blank areas of the map and move the edit menu controller out of modeSelect.

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Now that we've done #7577, the edit menu is also accessible on touch devices. Thus, implementing menu buttons for copy and paste would make these operations possible on mobile devices where keyboard shortcuts aren't generally available.