Add active-standby setting in SI properties schema.
Add local preference to service instance VMI.[active: 101, standby: 100]
Used with SNAT and LBAAS for active-standy HA

Change-Id: I81b46929647d66ff5a02f7b576b58c5a70764ce5
Merge "Add active-standby setting in SI properties schema. Add local preference to service instance VMI.[active: 101, standby: 100] Used with SNAT and LBAAS for active-standy HA" into R1.10