Allow broker configuration in scenarios

[josephmckinsey]

Sometimes, we may want to specify certain broker characteristics like timeout. It would be convenient to add this in the scenario JSON or as a parameter for oedisi build.

{
    "name": "simulation_name",
    "broker_configuration": {
         ...
     },
     "components": {...},
     "links": {...}
}

[josephmckinsey]

See #49 as well for what we want we want from this.