Cloud VM: mount data to /var/lib/docker (#8)

Since Nextcloud AIO manages itself and uses docker volumes, the easiest way to persisty all data in a separate disk is to just mount it to `/var/lib/docker`. This is still an easier long-term solution than managing the entire stack manually - we can always migrate (relatively) easily in the future anyway.

Reviewed-on: #8

infra/cloud/nextcloud/all-in-one.sh

@@ -9,7 +9,6 @@ docker run \
 --name nextcloud-aio-mastercontainer \
 --restart unless-stopped \
 --publish 8080:8080 \
---env NEXTCLOUD_DATADIR=/mnt/data/nextcloud \
 --env NEXTCLOUD_UPLOAD_LIMIT=16G \
 --env NEXTCLOUD_MAX_TIME=7200 \
 --env APACHE_PORT=11000 \