Update groups to support super admin authority level. (#198)

api/api.pb.go

api/api.pb.gw.go

api/api.proto

api/api.swagger.json

console/console.pb.go

console/console.proto

console/console.swagger.json

main.go

migrate/migrate-packr.go

migrate/sql/20180103142001_initial_schema.sql

server/api_group.go

server/api_link.go

server/api_unlink.go

server/console_gdpr.go

server/core_authenticate.go

server/core_channel.go

server/core_friend.go

server/core_group.go

server/core_notification.go

server/core_storage.go