* Use debian slim for docker builds

* changelog

* Update 828.bugfix

* Update yarn.lock
* Dockerfile: Install python3 and add git:// workaround for github.com
* CI: Apply git config to fix fetching from Github
* Upgrade matrix-appservice-bridge to v5.0.0; requires Node.js 16+

* Drop support for Node 12
Enable support for Node 18

* Don't be too hasty

* changelog

The tool has to be run in /data since it expects `discord-registration.yaml` to be in the working directory. However, the bridge itself can't be run from /data because it expects to be able to load the config schema from path relative to the working directory. The tools don't seem to need this schema and seem to run fine from /data.

Remove WORKDIR from dockerfile, since it breaks the bridge (it expects to find some things in the working directory that aren't there anymore)

Things need to be stored in a volume, so we also add a bunch of configuration options for moving the persistence around.