These changes go with those of elastic/kibana#142920.

As we formalize the process by which the Fleet package
installer will upgrade transforms more operations are
required for managing the transforms and the related
destination index:

1. Need to be able to add an alias on the transform
   destination index and adjust which indices it points
   to when upgrading the transform.
2. Need to be able to remove a default ingest pipeline
   from the settings of an old transform destination
   index during an upgrade that deletes the ingest
   pipeline.