add tag definnition for members of type=building relations and update the valdator warning

[skyper]

This is a follow-up of #21285, see my comment 8

Currently, there is no tag definition for members of type=building relations. #21285 added a warning about missing building=* for the relation, but the wiki requests to have building=* on the member with role outline. E.g.

• the preset should have some required tags for the members
  • at least for the relations, naming could be prettified with name_template
• a warning for different values of building=* on the relation and its outline member is useful
• the warning for missing building=* should be removed or downgraded to informal

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2022-01-02 21:24:43 +0100 (Sun, 02 Jan 2022)
Revision:18360
Build-Date:2022-01-02 20:26:19
URL:https://josm.openstreetmap.de/svn/trunk