REST API manage Notification Schemes

As a Jira app developer, I want to create update and delete notification schemes like I can do with all other schemes so that I can build apps with customized workflows with appropriate notifications for my app.

Minimum Acceptance Criteria:

• configure notification schemes to trigger notifications based on common events and send notifications to selected customer groups as it can be configured via the UI

Nice to have

• trigger custom events in workflows and allow notification schemes to be based on these custom events