feature[ats_ATS144309]: Move ConnectionHandler to skynet.core

Change-Id: Ib3d9de3be30cb8aad5ed76a76f959a86a73db76f
refactor: Remove unused DbInfo class

Change-Id: I970d615e52f204a60b549fce0b759739df47d25c
feature[ats_ATS144309]: Improve client side db sequence

Change-Id: I1ebab218e2986f38602d84b56c7b259a0b6e71d7