Optional wait-list service plan feature

[gberche-orange]

Expected behavior

To support https://github.com/orange-cloudfoundry/paas-templates/issues/2229

Add a way to map a broker-defined service plan onto a different broker and service plan

Given coab-mysql service is declared with plan:

• waitlist-dedicated

Given osb-cmdb is configured with plan-mapping config

• plans.mappingFromTo[waitlist-dedicated[brokerName]: static-creds-broker
• plans.mappingFromTo[waitlist-dedicated[planName]: no-op

When service instance is requested for coab-mysql service and plan waitlist-dedicated
Then broked service instance in using broker static-creds-broker and plan noop

Observed behavior

No such mapping feature yet.