Add ability to give action plug-ins in session creation.
Add handling for action-plug-ins in defautl workflow
Add database support
Dummy action plug-in added to see how it works. Will be removed before this
merges.
Documentation will be updated as review done
Story: 2003846
Task: #29160
Change-Id: I56c77df4937c16f419b6d963f5a5fa0642fc0d43
Signed-off-by: Tomi Juvonen <tomi.juvonen@nokia.com>