Add categories field to WebAppMeta
Add categories field to WebAppMeta

It defaults to "Network;" with a warning.

Spec: http://standards.freedesktop.org/menu-spec/latest/apa.html

Signed-off-by: Jiří Janoušek <2a48236b6dcae98c8c0e90f4673742773ee17d91@gmail.com>

tiliado/nuvolaruntime,tiliado/nuvolaruntime,tiliado/nuvolaruntime,tiliado/nuvolaruntime