Support 'supported-service.*' features requests coming from VMs. Set
such features directly (allow only value '1') and remove any not
reported in given call. This way uninstalling package providing given
service will automatically remove related 'supported-service...'
feature.
FixesQubesOS/qubes-issues#4402
Rename events:
- domain-feature-set -> domain-feature-set:feature
- domain-feature-delete -> domain-feature-delete:feature
- domain-tag-add -> domain-tag-add:tag
- domain-tag-delete -> domain-tag-delete:tag
Make it consistent with property-* events. It makes more sense to
include tag/feature name in event name, so handler can watch a single
tag/feature - which is the most common case. Otherwise, most handlers
would begin with `if feature == '...'` anyway, wasting time on most
events.
In cases where multiple features/tags should be handled by a single
handler, it is now possible to register a handler with wildcard, for
example `domain-feature-set:*`.
