mdstudio 'service' endpoints

[marcvdijk]

Would be good to have a few endpoints at the mdstudio core level to do such things as:

• get the (latest) registered requests and response JSON schemas for a given service endpoint.
• validate if a endpoint is available within the current microservice ecosystem
• refresh registered schemas for a microservice without the need to rebuild the full DB schema
  collection. Especially nice during development where it is possible and likely that
  mistakes/changes will be made
• query endpoint to allow a user to query for endpoints based on JSON schema metadata such as
  description, title, keywords, etc.