Offline self-hosting (fully local instance)

[Andrew15-5]

Context: #1405 (reply in thread).

Currently, it's impossible to run the account-enabled version offline, as you are required to use Firebase for account auth stuff.

Not only do you have to have an Internet connection to use a local/self-hosted instance, but you also have to have a Google account (and mess with API keys), which I and many others would prefer not to be a requirement to practice typing offline.

From my limited knowledge, you would have to mess with the API endpoints, which there are a lot of (I think?). The project seems to use MongoDB already, which is also NoSQL type database. Didn't work with Firebase, but I don't get why you need both. I assume if you can just cut away Firebase and leave everything working with just MongoDB, it would already be an MVP. Anyway, I guess you would need to add an option to enable/disable Firebase integration, and then you could use dev/prod version with or without Firebase.

I'd like to work on this, but honestly I have more important stuff to do (I also need to read through the code base for the first time). So, maybe at some point I can actually get into making a draft PR.