This commit adds support data stream support to CCR's auto following by making the following changes:
* When the auto follow coordinator iterates over the candidate indices to follow,
the auto follow coordinator also checks whether the index is part of a data stream and
if the name of data stream also matches with the auto follow pattern then the index
will be auto followed.
* When following an index, the put follow api also checks whether that index is part
of a data stream and if so then also replicates the data stream definition to the
local cluster.
* In order for the follow index api to determine whether an index is part of a data
stream, the cluster state api was modified to also fetch the data stream definition
of the cluster state if only the state is queried for specific indices.
When a data stream is auto followed, only new backing indices are auto followed.
This is in line with how time based indices patterns are replicated today. This
means that the data stream isn't copied 1 to 1 into the local cluster. The local
cluster's data stream definition contains the same name, timestamp field and
generation, but the list of backing indices may be different (depending on when
a data stream was auto followed).
Closes#56259
c4c3c8b422