Change service VM connectivity

Add new config option(boolean) "connect_share_server_to_tenant_network".
If it is not set we use old VM connectivity method i.e. route request to
share into service network/subnet.

If it is set, we use direct VM connection. In this case share VM will
have 2 interfaces: eth0 attached to service network/subnet and eth1
attached to tenant network.

Implements blueprint direct-service-vm-connectivity
Change-Id: I794a7ce158a3f17a55f4277b669ce0bb8ecfc180
Merge "Change service VM connectivity"