Draw admin_level borders only with boundary=administrative

[naoliv]

Draw an area with office=government + admin_level=2 and see how it's rendered as a boundary.

Personally I am against using admin_level for stuff other than administrative boundaries (and heritage), but people are starting to use it with office=government

See this thread ​https://lists.openstreetmap.org/pipermail/tagging/2017-July/032832.html + ​https://wiki.openstreetmap.org/wiki/User_talk:Math1985#admin_level_with_office.3Dgovernment

So it seems that JOSM should start to draw borders only when we have boundary + admin_level

[Klumbumbus]

In 13083/josm:

fix #15503 - draw administrative boundaries only if boundary=administrative is tagged; add a warning for usage on nodes (used 330 times atm)

[Klumbumbus]

(This doesn't mean that the usage of admin_level on e.g. office=government is discouraged (thats another topic), but the rendering was and is for boundary areas and not for possible other uses.)

[Klumbumbus]

In 13084/josm:

see #15503 - simplify mapcss rules, warn about boundary=administrative without admin_level