Indexer to support new endpoint to expose Indexing Schema converted from Schema Service

Summary
The Indexer service needs to be modified so that it exposes the output of Schema Service schema conversion into Storage Schema schemas. This is needed for developers as well as operators of the system in order to check quality and expected results in Search.
Details
The Indexer has been modified to support schemas from the Schema Service as well as the original Storage Schemas which are still the basis for actual indexing by Elastic. Here is the issue:
Indexer to Support Schema Service schemas
However, from a support perspective, the fact that Schema Service schemas are converted internally by the Indexer to produce actionable Storage Schemas is problematic in that it doesn't allow developers and consumers any insight as to the converted schema and how or whether the conversion has been done successfully.
The proposed solution is to add a new endpoint to the Indexer service that will return the converted Schema representation based on the input Schema Service schema. This will make the schema conversion process transparent and allow checks on the content as well as allow better debugging of either Schema Service schemas or the conversion process itself.

Input = Schema Service Schema (JSON representation)
Output = Index Schema

Note that the Input Schema can be from any source (i.e. not necessarily resident in Schema Service already) and will be stateless on the Schema and Storage Schema Services themselves.