added some new classes

Signed-off-by: Blessing Osakue <iyoworks@gmail.com>
removed separate management of entities

Signed-off-by: Blessing Osakue <iyoworks@gmail.com>
added timestamp support to AttributeType

Signed-off-by: Blessing Osakue <iyoworks@gmail.com>
added merge bag method to alert bag

Signed-off-by: Blessing Osakue <iyoworks@gmail.com>