Create/Edit transcriptions directly from the sidebar

Refs https://gitlab.com/arkindex/requests/-/issues/561

Depends #866 (closed)

⚠ This will be a large change, as it would remove the transcription modal in the end (and would need validation from the whole team before releasing)

The "add" button for transcription would display a new textarea right next to it, taking the whole space available (1/3rd of the viewport currently).

Every existing transcription would have an edit button that allows raw edition of the transcription through a dedicated textarea (the grey box becomes a texarea).