Added data models
Moved Lbaas SqlAlchemy models to its own module

Change-Id: I5155d3e2c7c96b2c1b7148a63087e130703f122a

Plugin access DB through composition now

Change-Id: I4c084447324bfbc73210ddc0c03c764aa03dcbc1
Fixed sync driver for db changes

Change-Id: I4149a7726e86f8b7ce299ca5a5290ea90009f554