bgpd: Add autocomplete for community/large/extcommunity stuff

bgpd: Add autocomplete for community/large/extcommunity stuff

```
exit1-debian-9(config)# route-map test1 permit 10
exit1-debian-9(config-route-map)# match community ?
  (1-99)               Community-list number (standard)
  (100-500)            Community-list number (expanded)
  COMMUNITY_LIST_NAME  Community-list name
     testas
exit1-debian-9(config-route-map)# match large-community ?
  (1-99)                Large Community-list number (standard)
  (100-500)             Large Community-list number (expanded)
  LCOMMUNITY_LIST_NAME  Large Community-list name
     LCL-ORIGINATED-ALL
exit1-debian-9(config-route-map)#
```

Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com>