Differentiate reltoolbox "create multipolygon" from core "create multipolygon"

[simon04]

Since

• r3704, JOSM core is capable of creating multipolygons
• #9492, JOSM core is capable of updating multipolygons

As far as I see, reltoolbox has special handling for boundary relations. Thus the "create multipolygon" of reltoolbox could be renamed to hint this special/additional feature in comparison to JOSM core.

This is a follow-up ticket for the discussion from #9492.

[Don-vip]

I'd prefer not use milestones for plugins as it does not really apply :)

[Zverikk]

As an author of reltoolbox plugin, I am against of moving actions out or renaming them. "Create multipolygon" action of reltoolbox is a lot more complex than the one in JOSM: for example, it can create multiple multipolygons at once, or add an arc to an existing multipolygon. Special handling of boundary relations is just a tip of the algorithm. Also, reltoolbox panel groups all relation actions, and it will be very unwise to spread them across JOSM interface.