Allow declaring upstreams and listen endpoints on different hosts

[3nprob]

Right now the binary makes specific assumptions that doesntream services are run on the local host precisely matching the setup resulting from running a fully managed opendex-docker stack.

It also seems to me like there currently are some requirements of this opendex-docker-api being able to execute commands inside the services, e.g. in

opendex-docker-api/service/boltz/boltz.go

Line 45 in cc7ab39

output, err := t.Exec1([]string{"wrapper", string(node), "getinfo"})

.

Would be good with some clarity on:

• Are these docker-invocations (like the boltz exampe above) currently required for having the integrations running, or are they just for debugging and logs ingestion? Can this be disabled through configuration?
• Apart from specifying the right hosts and ports in the config.json read in https://github.com/opendexnetwork/opendex-docker-api/blob/master/service/manager.go#L57, are any other changes required to make this work independently?