In this PR we enable all new data streams to be managed by the data
stream lifecycle by default. This is implemented by adding an empty
`lifecycle: {}` upon new data stream creation.
Opting out is represented by a the `enabled` flag:
```
{
"lifecycle": {
"enabled": false
}
}
```
This change has the following implications on when is an index managed
and by which feature:
| Parent data stream lifecycle| ILM| `prefer_ilm`|Managed by|
|----------------------------|----|----------------|-| | default | yes|
true| ILM| | default | yes| false| data stream lifecycle| |default |
no|true/false|data stream lifecycle| |opt-out or
missing|yes|true/false|ILM| |opt-out or missing|no|true/false|unmanaged|
Data streams that have been created before the data stream lifecycle is
enabled will not have the default lifecycle.
Next steps: - We need to document this when the feature will be GA
(https://github.com/elastic/elasticsearch/issues/97973).
* [DOCS] Update manual downsampling documentation to use TSDS
* Swap manual and ILM downsampling examples in nav
* Typo
* Update prerequisites based on review feedback
* Warn against deleting the old backing index.
* Clarify counter/gauge results
* Mention that the downsampled type is 'aggregate_metric_double'
