[DAPS] Index GtR outcomes

[jaklinger]

GtR projects have up to 13400 outcomes, which if stored as a nested field in ES leads to "mapping explosion" (for more info see index.mapping.nested_objects.limit in https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping.html).

The solution to this is to index outcomes as their own documents. That is a separate task, and hence this issue.