WIP: Debian installation instructions

.gitlab-ci.yml

api/compose/django/entrypoint.sh

api/config/settings/common.py

api/config/settings/production.py

api/config/settings/test.py

...i/providers/audiofile/management/commands/import_files.py

api/funkwhale_api/providers/audiofile/tasks.py

...nkwhale_api/providers/audiofile/tests/test_disk_import.py

api/manage.py

api/requirements.apt

api/test.yml

deploy/env.prod.sample

deploy/funkwhale-server.service

deploy/funkwhale-worker.service

deploy/funkwhale.target

deploy/nginx.conf

dev.yml

docs/changelog.rst

docs/conf.py

docs/importing-music.rst