Dropped engine setting, closing bug #7455.

Signed-off-by: Matheus Macabu <mkbu95@gmail.com>
Merge branch 'master' of https://github.com/HerculesWS/Hercules
Merge branch 'master' of https://github.com/HerculesWS/Hercules
Split use_sql_db into the three available: item_db, mob_db, mob_skill_db.

Signed-off-by: Matheus Macabu <mkbu95@gmail.com>