This commit adds support for system data streams and also the first use
of a system data stream with the fleet action results data stream. A
system data stream is one that is used to store system data that users
should not interact with directly. Elasticsearch will manage these data
streams. REST API access is available for external system data streams
so that other stack components can store system data within a system
data stream. System data streams will not use the system index read and
write threadpools.
Removes the `@timestamp` field mapping from several data stream index
template snippets.
With #59317, the `@timestamp` field defaults to a `date` field data type
for data streams.
This makes the data_stream timestamp field specification optional when
defining a composable template.
When there isn't one specified it will default to `@timestamp`.
Limit the creation of data streams only for namespaces that have a composable template with a data stream definition.
This way we ensure that mappings/settings have been specified and will be used at data stream creation and data stream rollover.
Also remove `timestamp_field` parameter from create data stream request and
let the create data stream api resolve the timestamp field
from the data stream definition snippet inside a composable template.
Relates to #53100
James Rodewig
Jay Modi
Joe Gallo
Dan Hermann
Przemko Robakowski
James Rodewig
Andrei Dan
Martijn van Groningen