Automatically refresh EnginioModel if identity was changed

The server automatically filter data based on ACL. It means that for
example after a succesfull login, a query result may be different.

[ChangeLog][Enginio] Automatically refresh EnginioModel contents
when identity changes.

Change-Id: Ied814d00b8cfb872fcd2ab2e6e7f51692e894890
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>
Allow update all item's properties in one EnginioModel::setData call

This change adds a new preconfigured role to EnginioModel, which
can be used to update multiple properties of an item in one function
call.

[ChangeLog] EnginioModel is able to update multiple
properties of an item in one setData function call. It can be achieved
by using Enginio::JsonObjectRole.

Change-Id: Ibc640d44f28d40fa349c6efdf65e3bb321a4fc79
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>