Replace deprecated SDL SdlInstance usage with xapp-frame's SdlStorage
APIs, which have been built on top of the valid SDL SyncStorage APIs.
Upgrade SDL version to v0.8.0.
Issue-Id: RIC-805
Signed-off-by: Timo Tietavainen <timo.tietavainen@nokia.com>
Change-Id: I04142853f74775ae40b71a0bef5431508acbb61a