Identify newly discovered collections in discovers table

[kiahna-tucker]

The client would benefit from being able to identify the discovered collections that are new to the specification. Phil proposed that the type of discovers.job_status be extended to include a change summary:

{
   "type": "success",
   "added": [{"resource_path": ["mytable"], "target": "acmeCo/capture/mytable", "disable": true}],
   "modified": [...],
   "removed": [...]
}