docs: re-home mkdocs sources within this repo (#2149)

docs/data-directory.md

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+Everything the container manages is located under the **container's** `/data` path, as shown here:
+
+![](img/level-vs-world.drawio.png)
+
+!!! note
+
+    The container path `/data` is pre-declared as a volume, so if you do nothing then it will be allocated as an anonymous volume. As such, it is subject to removal when the container is removed. 
+
+### Attaching data directory to host filesystem
+
+In most cases the easiest way to persist and work with the minecraft data files is to use the [volume mounting](https://docs.docker.com/storage/volumes/) `-v` argument to map a directory on your host machine to the container's `/data` directory. In the following example, the path `/home/user/minecraft-data` **must be** a directory on your host machine:
+
+    -v /home/user/minecraft-data:/data
+       ------------------------- -----
+        |                         |
+        |                         +-- must always be /data
+        |
+        +-- replace with a directory on your host machine
+
+When attached in this way you can stop the server, edit the configuration under your attached directory and start the server again to pick up the new configuration.
+
+With Docker Compose, setting up a host attached directory is even easier since relative paths can be configured. For example, with the following `docker-compose.yml` Docker will automatically create/attach the relative directory `minecraft-data` to the container.
+
+``` yaml title="docker-compose.yml"
+version: "3"
+
+services:
+  mc:
+    image: itzg/minecraft-server
+    ports:
+      - 25565:25565
+    environment:
+      EULA: "TRUE"
+    tty: true
+    stdin_open: true
+    restart: unless-stopped
+    volumes:
+      # attach a directory relative to the directory containing this compose file
+      - ./minecraft-data:/data
+```
+
+!!! note
+
+    if you have SELinux enabled, then you might need to add `:Z` to the end of volume mount specifications, [as described here](https://prefetch.net/blog/2017/09/30/using-docker-volumes-on-selinux-enabled-servers/).
+
+### Converting anonymous `/data` volume to named volume
+
+If you had used the commands in the first section, without the `-v` volume attachment, then an anonymous data volume was created by Docker. You can later bring over that content to a named or host attached volume using the following procedure.
+
+!!! note 
+
+    In this example, it is assumed the original container was given a `--name` of "mc", so change the container identifier accordingly.
+    
+    You can also locate the Docker-managed directory from the `Source` field obtained from `docker inspect <container id or name> -f "{{json .Mounts}}"`
+
+First, stop the existing container:
+
+``` shell
+docker stop mc
+```
+
+Use a temporary container to copy over the anonymous volume's content into a named volume, "mc" in this case:
+
+``` shell
+docker run --rm --volumes-from mc -v mc:/new alpine cp -avT /data /new
+```
+
+Now you can recreate the container with any environment variable changes, etc by attaching the named volume created from the previous step:
+
+``` shell
+docker run -d -it --name mc-new -v mc:/data -p 25565:25565 -e EULA=TRUE -e MEMORY=2G itzg/minecraft-server
+```
+
+### Locating filesystem path of anonymous volume
+
+The `Source` field from the output of this command will show where the anonymous volume is mounted from:
+
+``` shell
+docker inspect -f "{{json .Mounts}}" CONTAINER_NAME_OR_ID
+```
+
+!!! note
+
+    On Windows with WSL the volumes path is `\\wsl$\docker-desktop-data\data\docker\volumes`