[z2113] Implement support to track aura targets more genericly

Replace the old SingleTarget aura tracking with a more generic concept, and use this also for CONTROL_VEHICLE auras

Signed-off-by: Schmoozerd <schmoozerd@cmangos>

(based on commit [12165] - 7e0fb2f)

(based on commit [s1737] - e764577)