All settings from `witnet.toml` should be also customizable through the CLI

[aesedepece]

There's no good reason for all the settings in witnet.toml not to be also customizable through the CLI.

This would allow for more flexible setups where reading configuration from the filesystem is not convenient, and overriding settings temporary for the sake of testing some features without having a hundred witnet-whatever.toml files lying around.

Attention should be also given to naming those settings the same in both places, e.g. right now known_peers from witnet.toml is called --peers in the CLI.

[bertux]

I will try to work first on adding the option for the public IP because I need it for the next improvement of the Docker container