Support place multipolygons

[Zverikk]

Now place multipolygon (type=multipolygon, place=*, place_name=*) is listed in relation panels as "multipolygon (12345678, 4 members)". It is not useful. Please add support for place tag, so it is listed as, for example, "multipolygon ("place")", or "multipolygon ("Town name")" when name=* or place_name=* is specified (name=* takes precendence).

[stoecker]

Name and others are already used for naming. You just need to give your place a name (if it has one) or a comment/note. In my eyes this is anyway preferred, as usually you don't see anything within all these unnamed relations.

[Zverikk]

1. place_name is not used if there's no name=* tag.
2. when relation has natural=XXXX or landuse=XXXX, multipolygon is named "XXXX". When relation has place=*, multipolygon is still unnamed. I ask to fix this, so place polygons would be named and easily differentiable in relation list.

[stoecker]

Ok, there are 26000 place relations, maybe we should support it really.

[stoecker]

In [3918/josm]:

fix #5976 - support relation names for place relations