Add docker in readme

[docjyJ]

$ docker run \
--rm \
--name nextcloud-aio-mastercontainer \
--volume nextcloud_aio_mastercontainer:/mnt/docker-aio-config \
nextcloud/all-in-one:latest
Docker socket is not available. Cannot continue.
Please make sure to mount the docker socket into /var/run/docker.sock inside the container!
If you did this by purpose because you don't want the container to have access to the docker socket, see https://github.com/nextcloud/all-in-one/tree/main/manual-install.

A mistake... Sorry to create a lot of PR 😅