use uuid tokens and sql driver for token persistence
use uuid tokens and sql driver for token persistence

Upstream osad uses fernet tokens as the default. In rpc we want to
continue to use uuid for the time being, so this commit adds a var to
override the default.

Additionally, we also set the persistence driver back to sql

Partially-Closes: 258

mattt416/rpc-openstack,xeregin/rpc-openstack,sigmavirus24/rpc-openstack,andymcc/rpc-openstack,nrb/rpc-openstack,major/rpc-openstack,sigmavirus24/rpc-openstack,miguelgrinberg/rpc-openstack,mattt416/rpc-openstack,miguelgrinberg/rpc-openstack,andymcc/rpc-openstack,jacobwagner/rpc-openstack,byronmccollum/rpc-openstack,nrb/rpc-openstack,sigmavirus24/rpc-openstack,xeregin/rpc-openstack,andymcc/rpc-openstack,galstrom21/rpc-openstack,xeregin/rpc-openstack,shannonmitchell/rpc-openstack,BjoernT/rpc-openstack,stevelle/rpc-openstack,cfarquhar/rpc-openstack,rcbops/rpc-openstack,rcbops/rpc-openstack,darrenchan/rpc-openstack,darrenchan/rpc-openstack,stevelle/rpc-openstack,prometheanfire/rpc-openstack,cloudnull/rpc-openstack,hughsaunders/rpc-openstack,shannonmitchell/rpc-openstack,cfarquhar/rpc-openstack,robb-romans/rpc-openstack,busterswt/rpc-openstack,claco/rpc-openstack,cloudnull/rpc-openstack,byronmccollum/rpc-openstack,galstrom21/rpc-openstack,busterswt/rpc-openstack,robb-romans/rpc-openstack,darrenchan/rpc-openstack,busterswt/rpc-openstack,jacobwagner/rpc-openstack,major/rpc-openstack,BjoernT/rpc-openstack,mancdaz/rpc-openstack,hughsaunders/rpc-openstack,prometheanfire/rpc-openstack,miguelgrinberg/rpc-openstack,nrb/rpc-openstack,mattt416/rpc-openstack,claco/rpc-openstack,xeregin/rpc-openstack,git-harry/rpc-openstack,darrenchan/rpc-openstack,git-harry/rpc-openstack,mancdaz/rpc-openstack,stevelle/rpc-openstack,byronmccollum/rpc-openstack,claco/rpc-openstack,sigmavirus24/rpc-openstack