Allow secondary URL for webjson contacts

Context

Currently when adding contact that uses the webjson fuctionality to send out alerts to , only has a single URL which you can use. When this URL is down (which could happen, because you are about to alert on something), it would be nice if we can have a secondary URL to post to.

Wish

Can we add a secondary URL in that contact, which will be used, in case, let's say, the first URL times-out after 5 seconds or so (configurable maybe?)

THank you!