accel-ppp: T5688: Standardized pool configuration in accel-ppp
Standardized pool configuration for all accel-ppp services.
- Only named pools are used now.
- Allows all services to use range in x.x.x.x/mask and x.x.x.x-x.x.x.y format
- next-pool can be used in all services
- Allows to use in ipoe gw-ip-address without pool configuration which allows to use Fraimed-IP-Address attribute by radius.
- Default pool name should be explicidly configured with default-pool.
- In ipoe netmask and range subnet can be different.
(cherry picked from commit 422eb463d413da812eabc28706e507a9910d7b53)