Merge #2178

2178: Refacto docker r=irevoire a=irevoire

closes #2166 and #2085

-----------

I noticed many people had issues with the default configuration of our Dockerfile.
Some examples:
- #2166: If you use ubuntu and mount your `data.ms` in a volume (as shown in the [doc](https://docs.meilisearch.com/learn/getting_started/installation.html#download-and-launch)), you can't run meilisearch
- #2085: Here, meilisearch was not able to erase the `data.ms` when loading a dump because it's the mount point
Currently, we don't show how to use the snapshot and dumps with docker in the documentation. And it's quite hard to do:
  - You either send a big command to meilisearch to change the dump-path, snapshot-path and db-path a single directory and then mount that one
  - Or you mount three volumes
- And there were other issues on the slack community

I think this PR solve the problem.
Now the image contains the `meilisearch` binary in the `/bin` directory, so it's easy to find and always in the `PATH`.
It creates a `data` directory and moves the working-dir in it.
So now you can find the `dumps`, `snapshots` and `data.ms` directory in `/data`.

Here is the new command to run meilisearch with a volume:
```
docker run -it --rm -v $PWD/meili_data:/data -p 7700:7700 getmeili/meilisearch:latest
```

And if you need to import a dump or a snapshot, you don't need to restart your container and mount another volume. You can directly hit the `POST /dumps` route and then run:
```
docker run -it --rm -v $PWD/meili_data:/data -p 7700:7700 getmeili/meilisearch:latest meilisearch --import-dump dumps/20220217-152115159.dump
```

-------

You can already try this PR with the following docker image:
```
getmeili/meilisearch:test-docker-v0.26.0
```

If you want to use the v0.25.2 I created another image;
```
getmeili/meilisearch:test-docker-v0.25.2
```

------

If you're using helm I created a branch [here](https://github.com/meilisearch/meilisearch-kubernetes/tree/test-docker-v0.26.0) that use the v0.26.0 image with the good volume 👍 
If you use this conf with the v0.25.2, it should also work.

Co-authored-by: Tamo <tamo@meilisearch.com>

Dockerfile

@@ -27,9 +27,20 @@ ENV     MEILI_SERVER_PROVIDER docker
 RUN     apk update --quiet \
         && apk add -q --no-cache libgcc tini curl
 
-COPY    --from=compiler /meilisearch/target/release/meilisearch .
+# add meilisearch to the `/bin` so you can run it from anywhere and it's easy
+# to find.
+COPY    --from=compiler /meilisearch/target/release/meilisearch /bin/meilisearch
+# To stay compatible with the older version of the container (pre v0.27.0) we're
+# going to symlink the meilisearch binary in the path to `/meilisearch`
+RUN     ln -s /bin/meilisearch /meilisearch
+
+# This directory should hold all the data related to meilisearch so we're going
+# to move our PWD in there.
+# We don't want to put the meilisearch binary
+WORKDIR /meili_data
+
 
 EXPOSE  7700/tcp
 
 ENTRYPOINT ["tini", "--"]
-CMD     ./meilisearch
+CMD     /bin/meilisearch