Use new ServiceBrokerApiUnreachable exception
Use new exception format

[#55737448]
Refactor HttpError and NonResponsiveHttpError

[#55737448]
Finalized the new error response format for the cloud controller.

An error from CC now might look like this:

{
  code: 10001,
  description: "Error provisioning service: Error from AppService: Your pants are on fire"
  types: [ "ServiceBrokerBadResponse", "HttpResponseError"],
  backtrace: ["here.rb:123", "there.rb:5676"]
  http: {
    status: 500,
    uri: "http://broker.example.com/v2/service_instances/ABC-DEF-GHI",
    method: "PUT"
  }
  source: {
    description: "Error from AppService: Your pants are on fire"
    types: [ "AppServiceError", "HttpResponseError"],
    backtrace: ["somewhere.rb:123", "somewhereelse.rb:5676"],
    http: {
      status: 500,
      uri: "http://appservice.example.com/whatever/their/url/is",
      method: "PUT"
    },
    source: "SOME WEIRD TEXT FROM APPSERVICE"
  }
}

[Finishes #55737448]