Make external production dependencies opt-in
There is a number of external dependencies included in production that should be opt-in and configurable instead of being shipped by default.
The ones I've found include: Algolia, Sentry and Doorbell. Some of them have the configuration hard-coded in the source, and others don't make sense if the opt-in CONNECT_WITH_MOTHERSHIP
env variable is set to False.
There is also a couple of images whose url is hard-coded in the source. This can have unintended consequences, for example the MoodleNet logo is currently broken in moodle.net/login. I also don't think it's appropriate to link gitlab raw files for this purpose.
I also noticed that fonts are configured with a googlefonts script. I suppose this one could be included out of the box. But I think it'd be nice to prevent Google from tracking all MoodleNet instances :).