Repose | Change export format

Closes #337 (closed)

Testing

1. Serve the Repose app version and answer some questions
2. Go to https://localhost:4200/repose. You should see the CSV and the JSON outputs
3. Clicking "Send Data" creates a zip archive containing a CSV and a JSON file with the respective contents and sends it to the Nextcloud server. You can access it through the link posted in Mattermost. The filename will be null because you don't have a Repose pseudonym/passphrase, this is ok (not relevant for this MR).
4. Download and unzip the archive and check the files