Add support for Quechua language in subtitles and transcriptions

[NamFra]

Feature Request

Is your feature request related to a problem or unsupported use case? Please describe.

We have received a request to add support for the Quechua language for subtitles and transcriptions in Marsha Video.
The course is set to start in early November.

Describe the solution you'd like

Add support for the Quechua language (qu code) across all relevant functionalities, including timedtexttrack, signtrack, and transcriptions.
If possible, ensure that it also works for automatic transcription with audiotrack.

Discovery, Documentation, Adoption, Migration Strategy

Languages used in Marsha seem to be based on the languages that Django supports out of the box:

• Settings: https://github.com/django/django/blob/main/django/conf/global_settings.py#L53
• Documentation: https://docs.djangoproject.com/en/5.1/ref/settings/#languages

I hope the language list can be easily extended. Feel free to let me know if that's not the case! 🙏