Align with oni configuration of remote structural indexes and change it to origins

[moisbo]

Here:

oni-ui/lib/Indexer-remote.js

Line 24 in b09563d

this.key = configuration.api.structural.key;

like here: https://github.com/Language-Research-Technology/oni/blob/1eab3e90e024120b5a59c3518add976e1f586ad1/src/routes/object/index.js#L106