Invidious gained support to read its configuration from an env var
instead of config file in e3c10d779d.
Unfortunately, Docker doesn't allow newline characters in env var
values (see [0]) which means we can only provide a proper YAML config
by using the inlined configuration in docker-compose.yml which,
unfortunately, is tracked by Git. Once support for multiline env var
values has been added to Docker, we should migrate and read the config
from a .env file instead (which is not tracked by Git).
[0]: https://github.com/docker/compose/issues/3527
