Ability to add "tag" for the static routes.
Proposed CLI:
```
set protocols static route 203.0.113.6/32 blackhole tag 666
set protocols static route 203.0.113.6/32 next-hop 192.0.2.1 tag 666
```
In the FRR:
```
r5(config)# ip route 203.0.113.6/32 blackhole tag 666
r5(config)# ip route 203.0.113.6/32 192.0.2.1 tag 666
```
One of the uses cases it easy to use in route-maps for blackholing (we allow match tags but we can't set tags for routes right now)
```
set policy route-map ISP01 rule 10 match tag 666
set policy route-map ISP01 rule 10 set community 111:666
set policy route-map ISP02 rule 10 match tag 666
set policy route-map ISP02 rule 10 set community 222:666
```