Adding PDF dependency by default for web variant as a search will result in an error without installing this. In case it is not installed it maigret web will return to the landing page and will present an error in the logs.
Multiple best practices applied as below:
- Replace deprecated `MAINTAINER` with `LABEL maintainer`
- Remove additional `apt clean` as it'll be done automatically
- Use `apt-get` instead of `apt` in script, apt does not have a stable
CLI interface, and it's for end-user.
- Put `apt-get install` & apt lists clean up in the same command
- Use `--no-install-recommends` with `apt-get install` to avoid install
additional packages
- Use `--no-cache-dir` with `pip install` to prevent temporary cache
- Use `COPY` instead of `ADD` for files and folders
- Use spaces instead of mixing spaces with tabs to indent
Size change by the refactor, almost 100MB saved:
```
REPOSITORY TAG IMAGE ID CREATED SIZE
maigret after 9e70c65dde32 1 minutes ago 543MB
maigret before a683f2b71751 7 minutes ago 635MB
```
