router_readconfig: add support for parsing/storing multiple dests for match
router_readconfig: add support for parsing/storing multiple dests for match

The routing doesn't take this into account, but match can now take
multiple destinations.  Next commits should make this operational.

grobian/carbon-c-relay,piotr1212/carbon-c-relay,lyft/carbon-c-relay,piotr1212/carbon-c-relay,grobian/carbon-c-relay,piotr1212/carbon-c-relay,lyft/carbon-c-relay,piotr1212/carbon-c-relay,lyft/carbon-c-relay,grobian/carbon-c-relay