[api] in event mails treat maintainers of devel package as maintainer too

We'll see if we need to split this into 2 roles or can live with that
[webui] add an icon to the configure link

otherwise it looks out of place
[webui] fix template name for spider
[api] yet another rework of the subscription logic

We need to consider the case where there is no default in the database but the
users have a setting. Somehow this slipped my mind
[webui] fix comment requests

creator role does not make sense for CommentforPackage
[api] work on mail content for BuildFail emails