Core/Help: Clean up HelpManager interface and users

Change-Id: Ia6edf583f2a002d7c6f4878df670a78614ea087d
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>
QmlProfiler: Simplify QmlProfilerClientManagerPrivate

Change-Id: Ib43417ef11ba9d052869e5088dd4c0cc551261c6
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>