feat: Add default languages list in atlas (in discussion)

[OmarIthawi]

Add default Open edX system-wide languages to the atlas pull workflow to avoid updating 50 repos whenever default languages change.

Options:

1- No default languages
2- Store config within openedx-translations:translations/default-filter.yml which Atlas queries dynamically on each fetch

• My favorate because it's maintainer friendly in case someone wants to fork openedx-translations.
  3- Hardcode default languages within Atlas, keep it overridable via the --filter=ar,de,fr_CA argument
• My least favorate because we want different versions of Atlas work with different versions of openedx-translations and this change impede this use case.
  4- Hardcode as the ATLAS_FILTER environment variable which should be set by deployment maintainers
• Adds more effort to maintainers.

Background:

Currently default languages are specified in three ways:

• i18n_tool tx pull pulls relatively completely translated languages by default from Transifex
• Makefile of many repos has default set of languages e.g. https://github.com/openedx/frontend-app-learning/blob/ea2d7ed83975c6ec1ca5b66308338cd6317d9f89/Makefile#L2
• config.yaml which affectsi18n_tool tx pull' in many repos: https://github.com/openedx/edx-platform/blob/master/conf/locale/config.yaml#L8-L29

None of the approaches above is useful with OEP-58 and atlas because of its dependence on the transifex-client

[ehuthmacher]

@OmarIthawi I have added your issue to our Translation board with feedback: https://github.com/orgs/openedx/projects/50/views/2?pane=issue&itemId=39034714

The list of languages is updated here: https://openedx.atlassian.net/wiki/spaces/COMM/pages/3157524644/Translation+Working+Group