The index action allowed to set the id of a document dynamically,
however this was not allowed for the index or the type.
If a user wants to execute a search, modify the found documents and
index them back, then this would only work across a single index and a
single type. This change allows the watch writer to just take a search
result, read index and type out of that and configure this as part of
the index action.
On top of that the integration tests have been changed to become fast
running unit tests.
Original commit: elastic/x-pack-elasticsearch@640b085dd4
Alexander Reelsen
Lisa Cawley