Validator should not complain about width key on aeroway=runway

[AM909]

In r4878, validator incorrectly complains that it is suspicious to tag width=* on a runway (aeroway=runway) because it is not a highway/railway/waterway. aeroway should be added to this list of keys with which width is useful. In fact, it seems like such a general measurement key is applicable to almost any point or linear feature (where the user does not want to draw an area instead).

[Don-vip]

In 5064/josm:

fix #7460 - Validator should not complain about width key on aeroway=runway