Allow a user to set text orientation

Depends https://gitlab.com/arkindex/backend/-/issues/851 & https://gitlab.com/arkindex/backend/-/issues/853

When a user creates or updates a transcription, the user should be able to set the text orientation for that transcription.

A <select> with possible values should be displayed in the transcription creation/edition form.

By default, use the horizontal-lr value.