Allow pasting descriptors in dataset registration
Similar to uploading the list of accessions in the dataset, allow for pasting descriptor definitions (as in descriptor list import). In the case here, the server should search for matching descriptors in the database and return matches the the client that will display the matches and allow user to select the correct descriptors.
This function should not register new descriptors.
Users can then still add and remove descriptors in the next step (as is now).