CSV and JSON export are not implemented

[almereyda]

What's this issue about?

The submission export currently only allows XLSX export, with no option to get the other CSV or JSON forms, as suggested by the README. This issue tracks their implementation, following on from #124

https://github.com/ohmyform/ui/blob/23e67c8f7e65396782f48ef5dfeef56ec8e45da9/components/form/admin/export.submission.action.tsx

Expected behavior

• Allow to download CSV as well. The presence of @fast-csv/ parse and format in yarn.lock suggests this is somewhat anticipated. https://github.com/ohmyform/ui/search?q=csv&type=code
• Allow to download JSON as well. Ideally, this can also happen through the API by providing an authorization token, which would have to be created in the user profile first.

Actual behavior

When exporting submissions, they are delivered as an XLSX blob.

Steps to reproduce

1. Open the list of submissions.
2. Press export.

Environment

This is a Docker environment.