Draft: Add Related objects in the search index
The objects indicated in the canvas "related objects" will entry as a search field. For example: the 'metro' object has 'pulse' as a related object, when the user searches for 'pulse' they will receive 'metro' as a possible answer. This commit doesn't do the reverse (to give the object 'pulse' when the user searches for 'metro').
TODO: Add a link to the objects in "Related objects"