bgpd: Allow setting BGP [large]community in route-maps
Before:
```
spine1-debian-11(config-route-map)# bgp community alias 65001:65001 test1
spine1-debian-11(config)# route-map rm permit 10
spine1-debian-11(config-route-map)# set community 65001:65001
% Malformed communities attribute
```
After:
```
spine1-debian-11(config)# bgp community alias 65001:65001 test1
spine1-debian-11(config)# route-map rm permit 10
spine1-debian-11(config-route-map)# set community 65001:65001
spine1-debian-11(config-route-map)#
```