Reorganizing workflow: Git and Wiki

[dennisguse]

Currently, the app and the content are two separate Git repositories (content is only a wiki backed by git).

This has the advantage that the technical part (aka the app) and the content are separated.
However, there are three problems regarding the wiki:

1. no translations into other languages (using tools like weblate)
2. no PR process for content changes
3. a new app release is required for actual content updates to take place

For these reasons, I would argue for two options:

1. convert the wiki into a real git repository (possibly with weblate support)
2. move the content of the wiki into the app repo (no submodule required; easier to see actual changes)

I would opt for the 2nd approach as it will reduce it makes app development simpler (as well as using translations tool).
This way it is easier to determine if a new app release is required due to content changes.