Add language attribute for projects and tutorials

[ofr1tz]

Currently there is no way to define the language of a project. Most projects and their descriptions are in English, but there are exceptions (e.g. projects in French). A language attribute would allow a client to identify projects by language.

Manager-dashboard:

• [ ] define language options
• [ ] add a language selection input field in the NewProject view and the NewTutorial view
• [ ] check that language value is submitted to Firebase
• [ ] optional: display language in projects overview page

Firebase

• [ ] adjust database rules to allow filtering by language

Python workers

• [ ] Handle new attribute in project and tutorial creation
• [ ] store new attribute in Postgres
• [ ] adjust project table schema in Postgres

[danbjoseph]

Hi @ofr1tz, how language works within the app is something the community and governance team are interested in improving. One direction we've discussed is enabling the translation of projects and tutorials. So that any single project could exist with multiple languages. This issue seems to plan things out in a slightly different direction. It would be good to discuss this in more detail; perhaps on a community call or during roadmapping sessions we will plan in the near future.