LBaaS: move agent based driver files into a separate dir
LBaaS: move agent based driver files into a separate dir

Replace agent based driver files from haproxy driver dir
Same for unit tests files

Finalizes blueprint lbaas-common-agent-driver

Change-Id: Ibff85a9c2e1f1c59d72616836d56a697dce72c59

moshele/old-networking-mlnx