- Adds audit logging level to internal logger
- Closes #730 

The main changes for the PR are in `logger.go` and `audit.go` where we
add the new AUDIT log level and then add a specific method to the logger
to log rewrap requests as an example. More detailed changes for other
audit calls will be done as part of #719

Examples of rewrap success log:
```json
{
  "time": "2024-05-21T11:03:18.910724-04:00",
  "level": "AUDIT",
  "msg": "{\"id\":\"4e027444-3496-4a6d-9e95-f44be19e341c\",\"object\":{\"type\":\"data_object\",\"id\":\"a96b1e6a-177d-11ef-a5c4-06f27729b9a5\",\"attributes\":{\"attrs\":[\"https://example.com/attr/attr1/value/value1\"],\"dissem\":[],\"permissions\":[]}},\"action\":{\"type\":\"read\",\"result\":\"success\"},\"actor\":{\"id\":\"68f9d36d-e103-4518-8258-70fe7cc87c90\",\"attributes\":{\"attrs\":[],\"dissem\":[],\"permissions\":null}},\"eventMetaData\":{},\"clientInfo\":{\"userAgent\":\"\",\"platform\":\"kas\",\"requestIp\":\"\"},\"diff\":{},\"timestamp\":\"2024-05-21T11:03:18-04:00\"}",
  "namespace": "kas"
}
```

Parsed JSON string of audit log message:
```json
{
  "id": "4e027444-3496-4a6d-9e95-f44be19e341c",
  "object": {
    "type": "data_object",
    "id": "a96b1e6a-177d-11ef-a5c4-06f27729b9a5",
    "attributes": {
      "attrs": [
        "https://example.com/attr/attr1/value/value1"
      ],
      "dissem": [],
      "permissions": []
    }
  },
  "action": {
    "type": "read",
    "result": "success"
  },
  "actor": {
    "id": "68f9d36d-e103-4518-8258-70fe7cc87c90",
    "attributes": {
      "attrs": [],
      "dissem": [],
      "permissions": null
    }
  },
  "eventMetaData": {},
  "clientInfo": {
    "userAgent": "",
    "platform": "kas",
    "requestIp": ""
  },
  "diff": {},
  "timestamp": "2024-05-21T11:03:18-04:00"
}
```