awscli temporary files are not removed

In the onyxia-base docker image, some files are not removed after the installation of awscli: `\home\onyxia\work\awscliv2.zip` and files in the `\home\onyxia\work\aws` folder.

I believe these could be removed, but I am not completely sure whether there is any side effect.

If they are safe to remove, the `install-awscli.sh` could end with a cleanup operation, e.g.:

```
rm -rf aws awscliv2.zip
```

Start by locating install-awscli.sh used by the onyxia-base Docker image and inspect where awscliv2.zip and the aws folder are created. Build or run the image to confirm the installation still works, then verify that /home/onyxia/work/awscliv2.zip and /home/onyxia/work/aws are absent after installation.

Written by the indexing model from the issue text.