Add some CLI options

[Natim]

--help to see the available options --version to see the current version -c,--config to select the policies file

[leplatrem]

What would be the advantages over environment variables?

I see two main ways of running the application:

• via Docker (latest or specific version)
• via clone + make serve (current git tag)

[Natim]

I think env variables are a great thing while deploying or using Docker but CLI is also very great when you are using the tool yourself.

I don't ask for a lot of things just some help to makes it easier to use.

Maybe the --help can list the ENV variables to use.