v3 release

• Make new model fields non-nullable if appropriate (resource_id, collector_target.type)
• Drop model fields that are no longer used (board_id, pipeline_id)
• Make enums for Tickets.status, Tickets.ticket_type, and Tickets.priority
• Make enum for Builds.build_status
• StatusHistory.status should use the same enum as Tickets.status
• Make migration
• Adjust config/processors/schemas to use the new enums
• Copy over any files needed from any v1 modules (schemas, routes, tests)
• Remove unneeded exclude clauses from v2 schemas
• Remove v1 (schemas, routes, processors, tests)
• Remove v1 organization schema cache
• Update crud classes to use new resource_id and type fields
• Remove any feature flags that are no longer experimental (API_V2)
• Stale branches should ignore default branch
• Update dependencies
• Update cypress tests to target new v2 endpoints
• Update README