expose IncludeUsage to QML api
Summary:
RecentUsageModel can list all aps and docs,
only aps or only docs. make possible to control that from QML
Test Plan: the api works, all existing code has the same behavior as before
Reviewers: Plasma, davidedmundson
Reviewed By: Plasma, davidedmundson
Subscribers: davidedmundson, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D27782