Add service broker create binding schema

[Samze]

Why

The Open Service Broker API is proposing allowing brokers to define JSON schema for their configuration parameters. This will allow tooling to validate parameters and UIs to auto generate forms.

Schemas are to be defined as part of the catalog on a plan and support create/update parameters on a service instance and create parameters on a service binding (update does not exist yet).

The updated spec can be found here.

Example of what a new catalog with schemas will look like:

{
     ....
	"plans": [{
		"name": "fake-plan-1",
		"id": "d3031751-XXXX-XXXX-XXXX-a42377d3320e",
		"description": "Shared fake Server, 5tb persistent disk, 40 max concurrent connections",
		"schemas": {
			"service_instance": {
				"create": {
					"parameters": {
						"$schema": "http://json-schema.org/draft-04/schema#",
						"type": "object",
						"properties": {
							"billing-account": {
								"description": "Billing account number used to charge use of shared fake server.",
								"type": "string"
							}
						}
					}
				},
				"update": {
					"parameters": {
						"$schema": "http://json-schema.org/draft-04/schema#",
						"type": "object",
						"properties": {
							"billing-account": {
								"description": "Billing account number used to charge use of shared fake server.",
								"type": "string"
							}
						}
					}
				}
			},
			"service_binding": {
				"create": {
					"parameters": {
						"$schema": "http://json-schema.org/draft-04/schema#",
						"type": "object",
						"properties": {
							"billing-account": {
								"description": "Billing account number used to charge use of shared fake server.",
								"type": "string"
							}
						}
					}
				}
			}
		}
	}]
}

What

This PR just adds basic support for create binding schemas (create instance schemas functionality merged in #834 & update instance schema merged in #865). Schemas are parsed during registration, stored in the service plan model and retrieved on the /v2/service_plan/:guid api endpoint. If a broker does not provide a schema, then we default to an empty schema.

• Add create_binding_schema to plan model object
• Add migration to service_plans to include text blob for create_binding_schema
• Add support for create binding schema to catalog objects retrieved from broker.
• Change service_plans presenter to support create binding schemas
• Added create binding schema tests to the 2.13 service broker api spec

Notes

1. This PR is an extension of the Service broker create instance schemas #834 & Service Broker Create Service Instance Schema Validation #847 & Service broker update instance schemas #865
2. We have no updated the docs yet as this is still an experimental change.
   Feedback appreciated!

PR

• I have viewed signed and have submitted the Contributor License Agreement
• I have made this pull request to the master branch
• I have run all the unit tests using bundle exec rake
• I have run CF Acceptance Tests on bosh lite
  Sam

[cfdreddbot]

Hey Samze!

Thanks for submitting this pull request! I'm here to inform the recipients of the pull request that you and the commit authors have already signed the CLA.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/149960857

The labels on this github issue will be updated when the story is started.

[tusing]

Thanks for the PR, @Samze!

@matt-royal && @tusing - CF CAPI