ospfd: Support show intra-area network type in 'show ip ospf route' command

ospfd: Support show intra-area network type in 'show ip ospf route' command

User can now use 'show ip ospf route detail' command to distinguish
intra-area stub network and transit network.
Transit network will be displayed as 'N T prefix ...'.

NOTICE: Json output format has been changed, intra-area transit networks
will have a new attribute 'transit' and value is 'true'.
And 'adv' (means advertise router) change to 'advertisedRouter'.

Example output:

bsp-debianrt-exp1# show ip ospf route detail
Codes: N  - network     T - transitive
       IA - inter-area  E - external route
       D  - destination R - router

============ OSPF network routing table ============
N T  10.0.0.0/24           [32] area: 0.0.0.0
                           via 192.168.124.67, ens192
                           adv 10.0.0.5
N    10.0.30.0/24          [33] area: 0.0.0.0
                           via 192.168.124.67, ens192
                           adv 10.0.0.5
...

Signed-off-by: Zhiyuan Wan <h@iloli.bid>