Customize Ratel serving address

[danielmai]

By default Ratel serves the UI over :::8000 (all addresses). The -port flag exists today to customize the port (default: 8000). There should also be a flag to configure the address. For example, it can be useful to restrict the Ratel web server to only allow access via the server itself on localhost.

[paulftw]

Bad actors can run Ratel locally to bypass this restriction, so it doesn't introduce any extra security.
What are other reasons to add this feature?

[paulftw]

IIRC Ahmed already merged this in. Please reopen if more configuration is still needed