* (Doc+) Link API to parent Doc part1
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Co-authored-by: shainaraskas <shaina.raskas@elastic.co>
Co-authored-by: shainaraskas <58563081+shainaraskas@users.noreply.github.com>
Rather than initializing the failure store right away when a new
data stream is created, we leave it empty and mark it for lazy
rollover. This results in the failure store only being initialized
(i.e. an index created) when a failure has actually occurred.
The exception to the rule is when a failure occurs while the data
stream is being auto-created. In that case, we do want to initialize
the failure store right away.
We were seeing more and more common fields between "regular" backing indices and failure store indices (i.e. `indices`, `rolloverOnWrite`, `autoShardingEvent`). To avoid having to duplicate these fields (and possibly any future fields), we extract a class that contains these fields.
Adds the ability to configure a data stream to create a new kind of backing index called a failure store which will eventually be used to store error information when ingest pipelines fail to ingest a document or when a document fails to be parsed correctly by the configured mapping on the data stream.
