Use text orientation for transcription display

Every displayed transcription in the sidebar must support the orientation provided by the backend in https://gitlab.com/arkindex/backend/-/issues/852

Here is the table of conversion from our values to CSS:

• horizontal-lr is writing-mode: horizontal-tb;
• horizontal-rl is writing-mode: horizontal-tb; direction: rtl;
• vertical-lr is writing-mode: vertical-lr;
• vertical-rl is writing-mode: vertical-rl;