Add elements from selection in a dataset

Refs https://redmine.teklia.com/issues/3653
Depends backend#1564 (closed)

We want to expose the usage of UpdateDatasetSelection through the frontend as a new selection action named "Add elements to dataset".

When the action is clicked, a new modal appears, allowing the user to :

1. select a dataset for the current corpus
2. select a dataset set name for the selected dataset

Once both values are selected, the endpoint is called, and a notification is displayed to the user. The selection remains unchanged.