Document the configuration for business/decision central timeout

As per of the fix of RHDM-457 and RHPAM-769 we also need to document how customers can configure the connection timeout to avoid the issues above.

The configuration needed can be done in two ways, global on the OpenShift router or specific the business/decision central routes.

just need to add the annotation haproxy.router.openshift.io/timeout: 60s on the target route, here is a full example:

- kind: Route
  apiVersion: v1
  id: "${APPLICATION_NAME}-rhdmcentr-http"
  metadata:     name: "${APPLICATION_NAME}-rhdmcentr"
    labels:       application: "${APPLICATION_NAME}"
    annotations:       description: Route for Decision Central's http service.
      haproxy.router.openshift.io/timeout: 60s
  spec:     host: "${DECISION_CENTRAL_HOSTNAME_HTTP}"
    to:       name: "${APPLICATION_NAME}-rhdmcentr"

For the global settings, there is a few environment variables that can be set like described in this link: https://docs.openshift.com/container-platform/3.3/architecture/core_concepts/routes.html#route-specific-timeouts