Expose endpoint to retrieve ccm schema

[priojeetpriyom]

Description

In lisk-service, GET /api/v3/schemas endpoint is used to provide all schemas to the clients . We are extending the response of this endpoint with the ccm schema.

Motivation

lisk-service requires the ccm schema from the node to extend the above mentioned endpoint. The schema can also be part of system_getSchemas response if that is more suitable.

Additional Information

• Extend schemas endpoint lisk-service#1571