Port to Pecan/WSME for API v2

Routing either V1 or V2 using a Facade. By default, V1 is enabled
but can be deactivated by a confflag.

Pecan controller for Lease created using WSME i/o validation

Implements blueprint: pecan-wsme

Change-Id: I9047abece78632daa13fdebfea9fb8aaa3c60981
Merge "Port to Pecan/WSME for API v2"