This changes the `GET _data_stream/ds_name/_lifecycle` endpoint to
return the data stream name even if it doesn't have a lifecycle
configured.
e.g.
```
{
"data_streams": [
{
"name": "logs-nginx"
}
]
}
```
* Fix xcontent and tests
* Update docs
---------
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
This removes a redundant `lifecycle` field in the `PUT _lifecycle`
request.
Before we had
```
PUT _data_stream/logs-nginx/_lifecycle
{
"lifecycle": {
"data_retention": "7d"
}
}
```
This changes the request to
```
PUT _data_stream/logs-nginx/_lifecycle
{
"data_retention": "7d"
}
```
With PR we introduce CRUD endpoints which update/delete the data lifecycle on the data stream level. When this is updated it will apply at the next DLM run to all the backing indices that are managed by DLM.
Andrei Dan
Mary Gouseti