Add JobsManager implementation with tests

Add JobsManager implementation with tests

JobsManagerImpl implements JobsManager interface providing support
for jobs management. It uses provided WorkManager for managing
workers and Tunnels implementation of Tunneler for handling tunnels.

Tests base on usage of MockWorkersManager and MockTunneler
for mockuping access to workers and tunnels.

Change-Id: I4c469f32fc4f918641f69843567b39bfcce8da4c
Signed-off-by: Lukasz Wojciechowski <l.wojciechow@partner.samsung.com>
Signed-off-by: Maciej Wereski <m.wereski@partner.samsung.com>